At least 25 people have been killed after Syrian fighter jets bombed a Palestinian refugee camp in the capital Damascus, according to opposition activists.
The attack on the Yarmouk camp was part of a campaign by President Bashar al Assad's military to force back rebel forces from a swathe of territory that runs from the east to the southwest of the city.
Opposition activists said the victims had been sheltering in a mosque when it was hit by a rocket fired by a Syrian fighter jet.
The deadly air strike came as rebel fighters in the northern city of Aleppo claimed they had taken an army infantry base, the latest in a series of military installations to fall into the hands of the opposition.
A commander of the Islamist Tawheed Brigade said his men helped take the building after five days of fighting.
"At least 100 soldiers have been taken prisoners and 150 decided to join us. The soldiers were all hungry because of the siege," he said.
The complex, known as Hanano Barracks, includes an army base, a recruiting centre and a military school.
The pro-government daily Al-Watan said the military had left the base as part of a "tactical withdrawal" while waiting for reinforcement to arrive.
Syria is home to more than 500,000 Palestinian refugees, most living in Yarmouk, and both Assad's government and the mainly Sunni Muslim Syrian rebels have enlisted and also armed Palestinians as the uprising has spread.
Heavy fighting broke out 12 days ago between Palestinians loyal to Assad and Syrian rebels, together with a brigade of Palestinian fighters known as Liwaa al Asifah (Storm Brigade).
Clashes flared again after the air strike as Palestinians from the pro-Assad Popular Front for the Liberation of Palestine-General Command (PFLP-GC) fought Syrian rebels and other Palestinians, according to the UK-based Syrian Observatory for Human Rights group.
Meanwhile, Syrian Vice President Farouq al-Sharaa told a Lebanese newspaper that neither government forces nor opposition fighters would be able to win the war in Syria.
He said the situation in the country was heading from bad to worse and that a "historic settlement", involving the formation of a national unity government "with broad powers", was needed to end the conflict, according to comments carried by al-Akhbar newspaper.
Tthe leader of Lebanon's Hezbollah movement said there was no way the rebels would emerge victorious.
"The situation in Syria is getting more complicated (but) anyone who thinks the armed opposition can settle the situation on the ground is very very very mistaken," Hassan Nasrallah said.
The Shia Muslim movement is a close ally of the Assad regime and has been accused of sending fighters to Syria to help battle the rebels.
About 40,000 Syrians have been killed since the uprising against Mr Assad's rule began 21 months ago.