ANTAKYA, Turkey -- Syrian forces bombarded rebel strongholds Sunday in part of the capital city of Damascus and a car bomb exploded in the central Syrian city of Homs, as fierce fighting between government troops and rebels continued unabated.
The extraordinary assault on the outskirts of the nation's capital was the most intense fighting in four months, as government troops tried to stall rebels from advancing further into the seat of power held by Syrian President Bashar Assad.
Reports from state-run media said at least 15 people were killed and more than 20 were injured, some critically, after a car bomb went off on al-Hamra Street in an upscale section of Homs. Many Syrians fleeing fighting elsewhere in the city have settled in the area.
Video posted on the Internet showed flames and thick black smoke billowing up from the street in front of an apartment building.
In Damascus, Syrian forces fired rockets into suburban neighborhoods where rebels have advanced in the last week in an apparent effort to stop them from closing in on the city center that is the seat of government.
Activists said fighting continued for a fourth day around the Damascus international airport, but the government announced that it was open and flights were operating on schedule. Egypt Air said it would resume flights today.
The day's events suggested that the Syrian government is leaning more on its air force, as rebels have overrun some army bases and taken away heavy weaponry.
A group named the Aleppo Military Council announced that it was prepared to shoot down Syrian fighter jets. The group did not specify what it would use to shoot down the attacking planes, but said, "We are very ready to accomplish these attacks," implying it had missiles capable of taking them down.
The commander of a Damascus-based militia consisting of about 15 men said they had assassinated an air force officer last week and were prepared to kill more in an effort to drain the regime's air power.
"We waited for him in the street and shot him," said the commander, who used the nom de guerre of Abu Omar al-Shami during an interview in Turkey, where he said he had come to raise money to buy silencers for their pistols.
There also was heavy fighting Sunday in the countryside around Idlib in northwestern Syria. Refugees who arrived in Turkey on Sunday said the Syrian army had intensified the shelling of numerous farming villages where residents have taken part in anti-government protests.