Mass protests broke out across Syria on Friday, a day after at least 55 people were killed in twin bombings that marked the deadliest attack since the start of the anti-government uprising 14 months ago.

The car bomb explosions in Damascus Thursday were among a string of attacks that have occurred since U.N. observers arrived in Syria to monitor a shaky cease-fire brokered by international envoy Kofi Annan.

State television reported Friday that troops killed a suspected suicide bomber in the northern city of Aleppo. The report said the would-be attacker's car was filled with 1,200 kilos of explosives.

The Syrian government on Friday urged the U.N. Security Council to take action to combat terrorism, in the wake Thursday's blasts.

State media said the government made the plea in letters to the Security Council and U.N. chief Ban Ki-moon. It said “escalating crimes” were proof that Syria is facing terrorist attacks led by groups receiving foreign support.

U.N. observers toured Damascus on Friday as protesters against the government of President Bashar al-Assad gathered in several cities and towns. There were unconfirmed reports of some injuries.

Observer mission spokesman Neeraj Singh said the number of international monitors and staff members taking part in the mission had grown to 50.

“You have the world coming together, the world community coming together to be with the people of Syria to see in what way we can help. The most important thing being that violence in all its forms has to stop.”

However, there are growing concerns that Thursday's twin suicide bombings are a signal the situation is about get much worse, especially after U.S. Defense Secretary Leon Panetta told reporters U.S. intelligence indicates there is “an al-Qaida presence in Syria.”

Terror analyst MJ Gohel says the trend is worrisome.

“What we're seeing in Syria now is a very dangerous escalation of violence. It is becoming a lot more deadly, a lot more sophisticated.”

Gohel is executive director of the London-based Asia-Pacific Foundation. He said the twin suicide bombings in Damascus bear all the hallmarks of an al-Qaida attack, with the first blast designed to scare people out of their offices and buildings, and right into the second blast.

But Gohel warned it would be premature to blame al-Qaida.

“Ayman al-Zawahiri, who is now the leader of al-Qaida, has issued a number of messages urging the rebels in Syria to join the cause of al-Qaida but he has found no traction there whatsoever.”

Still, that has not stopped both the Syrian government and opposition groups from pointing a finger at the terrorist organization.

The head of Syria's main opposition group, in Tokyo Friday, blamed the Damascus bombings on al-Qaida-linked forces with ties to the Syrian government. Burhan Ghalioun accused the government of trying to sabotage the peace plan brokered by international envoy Kofi Annan.

Jeffrey White, a defense fellow at the Washington Institute and former analyst with the U.S. Defense Intelligence Agency, said such a scenario is certainly plausible. He added that there is a strong belief within the intelligence community that the Assad regime has ties with al-Qaida in Iraq.

But it's unlikely government forces would attack supporters, he said.

“For the regime to attack either directly or indirectly its own primary supporting mechanisms seems a little bit of a stretch.”

The Assad government accuses the opposition forces of siding with al-Qaida, something Bassam Imadi with Syrian National Council, strongly denied.

“The opposition doesn't benefit from that, the al-Qaida would lose a lot of supporters, if there are supporters at all. And again the opposition or the fighters on the ground, the Free Syrian Army or other people who are working with the Free Syrian Army, do not have the means or the explosives to start such explosions.”

Some analysts, including Arie Kruglanski, a terror expert and professor of psychology at the University of Maryland, say that the opposition is an unlikely culprit.

“I do not think that in the name of democracy or in the name of good governance people would be ready to commit suicide. Religion and jihadism are very powerful justifying ideology.”

Kruglanski said suicide bombings are the hallmark of religious extremism and that what the emergence of suicide bombers may indicate most strongly, is the level of anger and frustration building within Syria.

“It is possible that there is a rage and tremendous anger at the government which makes it easier to commit suicide bombing in order to take vengeance.”

Analysts say it will likely take time to determine exactly who is responsible for the growing number of bombings and suicide attacks. In the meantime, they warn Syria could become mired in a ever-messier conflict that could well descend into civil war.

And, if groups like al-Qaida do not have a strong foothold in Syria now, MJ Gohel says the escalating conflict could serve as an open invitation.

“Al-Qaida's strategy has always been to go into any country where there has been a breakdown of any kind of law and order and to perpetrate violence. And they would hope that in that chaos that they would have the capability to fill the vacuum and establish some kind of foothold, which they have done for instance in countries in the past like Afghanistan.”

The United Nations says more than 9,000 people have been killed in violence related to the anti-government uprising which erupted in March 2011.

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VIDEO:

AUDIO:

M J Gohel, Executive Director of the Asia-Pacific Foundation (English):

-interview by VOA's Jeff Seldin, saved as “OCN SYRIA – Gohel Interview” in House Shared Friday in Dalet 5.1e

– the following acts are saved as “”OCN SYRIA – Gohel 9 acts” in House Shared Friday in Dalet 5.1e

1.”What we're seeing in Syria now is a very dangerous escalation of violence. It is becoming a lot more deadly, a lot more sophisticated.”

2.”The two bomb blasts that went off on Thursday morning in the capital Damascus were really well-planned, highly destructive devices and planned in such a way that the first explosion would draw the people out of their offices and buildings and they would walk straight into the second explosion, which had at least a minimum of 450 kilograms of explosives. So we are looking at something very, very serious now beginning to take place.”

3.”The level of sophistication in this attack and the quality of the device of the device would point the finger at two or three suspects. One is, of course, the accusation that the Syrian government is making of the perpetrators being al-Qaida or a group linked to al-Qaida. On the other hand, the opposition are saying that the Syrian government itself is responsible for these explosions and that the Syrian government is trying to gain sympathy.”

4.”There really isn't enough evidence to suggest that al-Qaida has established any kind of ground operational capability in Syria.”

5.”Al-Qaida strategy has always been to go into any country where there has been a breakdown of any kind of law and order and to perpetrate violence. And they would hope that in that chaos that they would have the capability to fill the vacuum and establish some kind of foothold, which they have done for instance in countries in the past like Afghanistan. They're trying to do that in Yemen, also in Somalia.”

6.”Ayman al-Zawahiri, who is now the leader of al-Qaida, has issued a number of messages urging the rebels in Syria to join the cause of al-Qaida but he has found no traction there whatsoever.”

7.”When there is a political vacuum of this kind, what we find is that the best group which is organized to fill that vacuum is often the Islamists, as we've seen happening in Libya, in Egypt and in Tunisia also.”

8.”People, even the moderates, may find they have no option other than to align themselves with better organized, radical groups and therefore the future for Syria doesn't look very good for the moment.”

9.”The more violence that takes place, there could be fragmentation and there could be proliferation of different groups, and once that happens it will be very hard to negotiate with anyone.”

Arie Kruglanski, terror expert and professor of psychology at the University of Maryland:

-interview by VOA's Jeff Seldin, saved as “OCN SYRIA – Kruglanski Interview” in House Shared Friday in Dalet 5.1e

– the following acts are saved as “”OCN SYRIA – Kruglanski 10 acts” in House Shared Friday in Dalet 5.1e

1.”Suicide bombings are the hallmark of religious extremism, the kind of distorted version of Islam.”

2.”People do not commit suicide bombings unless they have a very strong and passionate ideological justification for it.”

3.”The fact that we see now suicide bombings in Syria suggest one of two possibilities that can be mentioned. One is that there are jihadists, al-Qaidaist elements within the opposition to Bashar al-Assad. The other possibility is the government has ways through its own imams, through its own persuaders to persuade young people to commit suicide in the name of jihadism.”

4.”It is possible that there is a rage and tremendous anger at the government which makes it easier to commit suicide bombing in order to take vengeance.”

5.”In order to take one's own life, vengeance is not enough. One has to have an overarching ideological cause. My suspicion is that there are ideologues there utilize the anger of young people and convince them to do what they are doing is martyrdom in the name of religious extremism.”

6.”I do not think that in the name of democracy or in the name of good governance people would be ready to commit suicide. Religion and jihadism are very powerful justifying ideology.”

7.”I think the government is certainly going to benefit from it because the fear of a minority in Syria, as well of the West, are that al-Qaida and other jihadist movements will take over and produce a government in Syria that will be worse than what we have had so far. So the government is definitely standing to benefit from it.”

8.”In a situation of great instability, al-Qaida and its affiliated movements stand to gain influence and they also are likely to be drawn to situations where they increase their influence and power.”

9.”In situation of instability such as in Yemen, in Libya, in Somalia, these third elements, these jihadist elements have wiggle room, have the possibility to gain influence, also on psychological grounds because in times of great uncertainty and turmoil very clear cut black and white extremists ideologies have particular appeal to people because they provide certainty and structure.”

10.”We can expect more to come because these suicide bombings are every effective. They produce massive casualties and they serve either the government or a third party that is attempting to gain influence.”

Jeffrey White, defense fellow at the Washington Institute and former analyst with the U.S. Defense Intelligence Agency:

-interview by VOA's Jeff Seldin, saved as “OCN SYRIA – White Interview” in House Shared Friday in Dalet 5.1e

– the following acts are saved as “”OCN SYRIA – White 7 acts” in House Shared Friday in Dalet 5.1e

1.”I think there are some salafists or jihadist elements working inside Syria, probably small in number and deeply underground, but I think they're probably present. But it's totally unclear who is responsible for yesterday's (Thursday's) bombing in Damascus or the previous bombings, just isn't certain who did it and there are number of candidates for who could have done it.”

2.”Al-Qaida and its affiliates like to operate in ungoverned areas or areas of instability where the government forces are weak or the society is disrupted. And they can go there. They can set up operation. They can conduct attacks on people they consider their enemies. They can gather forces and support.”

3.”There's a belief and some evidence that the regime supported salafist elements, including al-Qaida in Iraq, during its operations inside Iraq against the U.S. forces there and the emerging Iraqi government.”

4.”Certainly fits the government's narrative of being under attack by terrorists as opposed to freedom fighters or the normal Free Syrian Army types. So it fits what the government wants to portray the situation as. The problem is though is that many of these attacks are against the very forces the regime depends on for it survival.”

5.”For the regime to attack either directly or indirectly its own primary supporting mechanisms seems a little bit of a stretch.”

6.”There's plenty of other targets that are available that could be attacked using terrorist means that would cause great political shock, you know, hospitals, schools mosques, churches, markets, all the kinds of places that were attacked in Iraq.”

7.”We may be getting the beginning of a, or in the early stages of a bombing campaign in Syria. We've had a number of incidents now in Aleppo. We've had a number of incidents now in Damascus. And we've had some incidents in Idlib province of wither explosive devices being used or suicide-type bombings.”