The Syrian army fired rockets at a Damascus district on Saturday, trying to drive out insurgents fighting their way closer to the seat of President Bashar al-Assad's power.
As fighting that has killed 60,000 persists in the 21-month uprising turned civil war, Syria's deputy foreign minister visited Iran on Saturday, seeking to maintain the support of Assad's main regional ally.
Iran's Fars news agency said Faisal al-Makdad would meet President Mahmoud Ahmadinejad and other Iranian officials.
Government forces fired rockets at Jobar, a Sunni enclave close to the centre of Damascus, a day after bombarding Daraya, a suburb in the east and part of a crescent of rebel-held areas on the outskirts, said Housam, an activist in the capital.
"The shelling began in the early hours of the morning, it has intensified since 11 a.m., and now it has become really heavy. Yesterday it was Daraya and today Jobar is the hottest spot in Damascus," he said by Skype.
Western countries have so far shown no appetite for military engagement in Syria of the sort that helped oust Libya's Muammar Gaddafi in 2011, but NATO is sending U.S. and European Patriot surface-to-air missile batteries to the Turkish-Syrian border.
The United States military said U.S. troops and equipment began arriving in Turkey on Friday for the deployment. Germany and the Netherlands are also sending Patriot batteries, which will take weeks to deploy fully.
Turkey and NATO say the missiles are a safeguard to protect southern Turkey from possible Syrian missile strikes. Syria and allies Russia and Iran say they could presage eventual military action by the Western alliance.
Syria's war, the longest and deadliest of the conflicts that arose out of popular uprisings in Arab countries over the past two years, has killed at least 60,000 people, according to a United Nations tally released in recent days.
The war pits rebels, mainly drawn from the Sunni Muslim majority, against Assad, a member of the Shi'ite-derived Alawite minority sect, whose family has ruled Syria since his father seized power in a coup 42 years ago.
Syria's SANA state news agency said a journalist, Suheil al-Ali from pro-government Addouniya TV, had died of wounds sustained in an attack by terrorists, the term government media use to refer to rebels. Syria was by far the most dangerous country for journalists last year, with 28 killed.
The opposition-linked Syrian Observatory for Human Rights, which monitors the conflict from Britain through a network of activists on the ground, reported fighting and shelling on Saturday near Damascus, in the eastern Euphrates river town of Deir al-Zoor and near the central city of Hama.
Rebels have made big advances in the past six months, seizing swathes of territory in the north and east and an arc of suburbs on the outskirts of Damascus. However, their control over areas they hold is limited by Assad's air power.
Assad's forces still control most of the densely populated southwest around the capital, the Mediterranean coast, the main north-south highway and military bases across the country from which aircraft are able to strike at rebel-held areas.
The rebels appear to have failed so far to seize a northern air base at Taftanaz after an assault in recent days; the base is still in government hands and Observatory chief Rami Abdelrahman said it had been quiet since Friday.
Video posted by opposition activists on the Internet on Saturday showed the corpses of men, some of which had been mutilated. It was impossible to verify the provenance of the video or the identities of the victims. Both sides in the conflict have been accused of carrying out atrocities. The United Nations says government forces have been more culpable.