World

Heavy explosions shook the Syrian capital Saturday and helicopters circled overhead as rebels appeared to be renewing their offensive in the city, witnesses and activists said.

The fresh battles show that President Bashar Assad's victories could be fleeting as armed opposition groups regroup and resurge, possibly forcing the regime to shuffle military units to react to attacks across the country. The country's civil war has intensified in recent weeks as rebels focused on the country's two biggest cities, Damascus and Aleppo.

"We heard heavy bombing since dawn," a witness in Damascus told The Associated Press, asking that his name not be used out of fear for his personal safety. "Helicopters are in the sky."

Saturday's violence comes only two weeks after the government crushed a rebel run on Damascus that included incursions by fighters into downtown neighbourhoods and an audacious bomb attack that killed four members of Assad's inner circle.

The fighting in Damascus appeared likely to drain the army's resources as fighting stretches into its second week in Aleppo, 350 kilometres (215 miles) to the north.

Late Friday, Syria's official news agency SANA said government forces had hunted down the remnants of the "terrorist mercenaries" its term for the rebels in the capital's southern neighbourhood of Tadamon. It said several were killed and many others wounded.

Syria's uprising began in March 2011 with mostly peaceful protests against the regime, but the conflict has transformed into a civil war. Activists say 19,000 people have been killed.

As the fighting grinds on, Syria reached out to its powerful ally Russia on Friday. Senior Syrian officials pleaded with Moscow for financial loans and supplies of oil products an indication that international sanctions are squeezing Assad's regime.

Syria is thought to be burning quickly through the $17 billion in foreign reserves that the government was believed to have at the start of Assad's crackdown.