Syrian troops backed by tanks and helicopters have broken into a Damascus suburb following two days of shelling and intense clashes as part of a widening offensive by President Bashar Assad's forces to seize control of parts of the capital and surrounding areas from rebel fighters, activists said.
At least 15 people were killed in the offensive on Daraya, only few miles south west of Damascus.
Across the country, at least 100 people died in shelling and clashes, according to the Britain-based Syrian Observatory for Human Rights and the Local Coordination Committees.
The bloodshed coincided with the departure from the Syrian capital today of the last of the United Nations military observers after their mission headed by former UN secretary general Kofi Annan, meant to help end the bloodshed in Syria, failed.
As the country slides deeper into civil war, activist groups now routinely report the deaths of anywhere between a 100 and 250 people on a daily basis, but it is virtually impossible to verify these figures.
Residents of Damascus said troops were bombing Daraya and nearby Moadamiyeh from the Qasioun mountain overlooking Damascus. "It's just another regular day in Damascus," said a resident of the city of 1.7 million. "I woke up to the sound of explosions and it hasn't stopped since."
In the eastern part of the country, Syrian rebels waged fierce battles with regime troops in a town along the Iraqi border, capturing a string of security posts and the local police headquarters despite heavy government shelling and bombing runs by warplanes, activists said.
The seemingly intractable conflict in Syria has defied all attempts at mediation. Human rights groups say more than 20,000 people have been killed since the uprising against President Bashar Assad began in March 2011, and in the past month the fighting has spread from the country's smaller towns and cities to the regime strongholds of Damascus and Aleppo.
Mr Annan announced earlier this month that he will resign on August 31. He is to be replaced by veteran diplomat Lakhdar Ibrahimi on September 1.
In Damascus, Deputy Foreign Minister Faysal Mekdad said Syrian officials were "looking forward" to working with Mr Ibrahimi but said the crisis would continue as long as foreign countries were interfering. Mr Mekdad accused Turkey specifically of giving "terrorists", including al Qaida, free access to cross into Syria from Turkey.