Government shelling and security force gunfire have left at least three people dead across Syria as U.N. observers launch more tours to monitor a shaky cease-fire.

The opposition Syrian Observatory for Human Rights says two people were killed during security force raids in Idlib province on Saturday and a third person died during pre-dawn shelling in the flashpoint Hama region.

In another development, a video posted online says the al-Nusra Front militant group is responsible for massive twin bombings in Damascus, on Thursday, that killed at least 55 people.

Middle East analyst M.J. Gohel says the group recently began gaining prominence.

“This is a group that not a great deal is known about it. It emerged at the beginning of this year in January and it has a global Jihadist agenda and it calls its fighters Mujahadeen in the same was as the Taliban fighters.”

Gohel, the head of the London-Based Asia-Pacific Foundation, says the group's strengths and capabilities are unclear.

“This could be just a propaganda small group. Its not known what kind of ground capable operational capability it has. All we know is that it has made all kinds of claims.”

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

The unrest took place as U.N. observers continued to fan out across Syria to monitor the government and the opposition's compliance to a cease-fire brokered by international envoy Kofi Annan.

On Saturday, the monitors received 24 armored vehicles that were donated by the European Union.

EU ambassador to Syria Vassilis Bontosoglou said the vehicles show the EU's support of Mr. Annan's mission.

“This is an expression of commitment of the European Union to the Kofi Annan plan.””

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

Also Saturday, Turkish state-run media say two journalists who went missing in Syria in March have been freed as a result of Iranian mediation.

The news reports say the two men have been flown to Tehran.