Syrian government warplanes struck a large Palestinian refugee camp in the capital Damascus on Sunday, prompting a massive exodus, reported an opposition group.
At least eight civilians were killed in the bombardment of the Yarmuk camp in southern Damascus, added the Britain-based Syrian Observatory for Human Rights.
The attack was followed by fierce clashes inside the camp between rebels opposing the regime of President Bashar Assad and pro-government Palestinian militiamen, added the organization.
The Yarmuk camp is home to around 100,000 Palestinian refugees. State media have, in the past, reported that rebel forces had taken shelter in the camp, which could have prompted the attack.
A hospital in the area could not cope with the large number of the people injured in the airstrike and the ensuing fighting, added the Observatory.
Palestinians residing in Syria have largely stayed out of the 21-month conflict between Assad's troops and the insurgents seeking his ouster.
Rebels have recently been fighting government troops in and around Damascus, raising the possibility that Assad could lose his hold on the capital.
Elsewhere, government troops and rebels were battling for control of key military installations in the northern province of Aleppo, reported the Observatory.
The fighting was taking place near a military academy named after Assad, as well as at a government intelligence building, it added. Fighting was also raging in the vicinity of a military airport on the outskirts of Aleppo, said the organization.
The two sides have been fighting for months in Aleppo, Syria's biggest city, with rebels claiming major gains.
The Local Coordination Committees, a network of opposition activists, said that at least 100 people were killed Sunday in Syria, mainly in and around Damascus. News from Syria is difficult to verify as authorities have barred most foreign media from the country.
The UN warned on Sunday that violence in Syria is set to raise the number of Syrian refugees to 1.8 million by 2013 and urged the international community to boost its response to a conflict "unlike any other."
UN Refugee Agency High Commissioner Antonio Guterres told reporters in the Jordanian capital Amman that the UN was preparing a new aid appeal to meet the needs of a projected 1.1 to 1.8 million Syrian refugees by the end of 2013.
'We are facing the possibility of 2013 being much more difficult than 2012 - you can believe the financial needs for 2013 will be substantially higher," Guterres said.
In a regional tour earlier this month, UN chief Ban Ki-moon warned that the ongoing funding gap is hurting efforts to provide the basic needs of some 500,0000 registered Syrian refugees in Turkey, Jordan, Lebanon and Iraq.
Earlier on Sunday, Hezbollah leader Hassan Nasrallah said the rebels in Syria cannot emerge victorious from the 21-month-long conflict.
Nasrallah, a staunch ally of Assad, said: "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 mistaken."
Syrian rebels accuse the Shi'ite group of sending fighters to Syria to help Assad, who is trying to crush a revolt against his rule. The group denies these accusations.
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