Syrian rebels have seized control of a third border crossing with Turkey after fierce battles with government troops, as fighting raged in the key cities of Aleppo and Damascus.

VOA correspondent Elizabeth Arrott reported from the Syrian capital Wednesday that thick, black smoke was rising from contested suburbs there – and that residents are getting nervous.

“In large part, I think people are just a little more pessimistic. One gentleman today just said, 'This situation isn't bad. It's awful.'”

At the Tal Abyad crossing near Turkey, rebels tore down the Syrian flag as Turkish authorities quickly closed the area and prevented a crowd of people from attempting to storm the border and cross into Syria.

This is the first time forces fighting to overthrow Syrian President Bashar al-Assad have overrun a border zone in al-Raqqa province, most of which has remained solidly pro-government.

The Britain-based Syrian Observatory for Human Rights said rebels withdrew from three southern districts of Damascus after weeks of heavy combat and shelling. In the northern city of Aleppo, the army said rebels attacked several military positions in the east overnight and that helicopter gunships eventually drove them off.

The Observatory said 32 people have been killed nationwide so far on Wednesday, including 27 civilians, after 173 died the previous day.

VOA's Elizabeth Arrott says the fighting is starting to weigh on those living in the capital, although life goes on as people head to work and maintain a sense of normalcy.

“I think (for) people in the street, it's just not clear how you get – what the solution would be. How does this end? And, in fact, one analyst, a professor I was talking to today, gave the example of Lebanon, which is kind of frightening. That went on for 15 years.”

Arrott says many in Damascus also are worried about the bigger picture.

“No matter whose side they're (Syrians) on, I think there is a great sense this is a proxy war. There are varying interests from varying countries and super powers and neighbors. And it makes people feel a little bit, perhaps, these are issues far beyond their control.”

Also Wednesday, Iranian Foreign Minister Ali Akbar Salehi met President Assad and other officials in Damascus, to discuss proposals by regional powers to end the 18-month conflict. Iran, Syria's main Middle East ally, has denied accusations it is providing military aid to the Syrian government.

Following their meeting, Mr. Assad said the war engulfing Syria is targeting not only it but the “axis of resistance” – a term Syria, Iran and Lebanon's Shi'ite Hezbollah movement use to refer to their common opposition to Israel.

Meanwhile, Amnesty International said the Syrian government has been increasingly carrying out “relentless, indiscriminate” attacks against residential areas that appear to be aimed solely at punishing civilians seen as sympathetic to rebel forces.

The rights watchdog issued a report Wednesday based on its investigation earlier this month in Idlib, Jabal al-Zawiya and Hama provinces.

Amnesty's Donatella Rovera told VOA the situation in northern Syria has significantly deteriorated since the end of July when government forces were pushed out of most of the area.

“Since then they've been essentially striking from afar, both air bombardments and artillery and mortar shelling, which are of very little use for hitting military targets because they are aerial weapons.”

Rovera said such “battlefield weapons” have a wide impact radius and fall randomly over residential areas “with disastrous consequences for the civilian population.”

Amnesty reiterated calls made by human rights groups for the United Nations Security Council to refer the situation in Syria to the International Criminal Court for probes into possible war crimes.

It also warned that opposition fighters may turn to indiscriminate attacks, and it urged rebel groups to communicate to fighters that such violations will not be tolerated.

Earlier this week, a United Nations panel presented a finding blaming both sides in Syria for increasing the number of attacks against civilians.

The U.N. commission of inquiry said that although both government and anti-government forces have committed war crimes, the abuses by opposition forces has not reached the “gravity, frequency and scale” of those carried out by pro-government fighters.