Members of the Free Syrian Army walk through a neighbourhood in Aleppo.

Beirut -

The two kidnapped brothers of a Syrian rebel commander were killed on Thursday, a monitoring group said, as battles raged between rebels and army forces in several districts of Damascus.

The men were kidnapped on Wednesday night at an army checkpoint, said the Syrian Observatory for Human Rights.

It said they were found dead in the southern district of Qadam in the capital amid a sharp increase in reports of abductions across the country.

Amateur video posted on YouTube by activists showed the bodies of the two men, identified as Mohammed and Ahmed al-Zakh, covered in blood. The bead of one of the victims had been partly blown off.

The Observatory also reported fierce battles and army shelling in the Qadam neighbourhood, where anti-regime sentiment is strong, as well as shelling in nearby Assali.

Clashes also broke out elsewhere in Damascus, including in the the Sayyida Zeinab area in the southeastern outskirts, home to an important Shi'a Muslim shrine, said the Britain-based watchdog.

Kafr Zeita in the central province of Hama, one of the main arenas of the 17-month revolt against President Bashar al-Assad, also saw fierce shelling for the second consecutive day, activists reported.

“It is horrific that the towns that have seen the most consistent dissent by unarmed protesters should be subjected to such violence,” an activist who identified himself as Abu Ghazi told AFP via Skype.

A preliminary toll compiled by the Observatory said that at least 17 people were killed in violence across Syria on Thursday, a day after 176 people - most of them civilians - died. - Sapa-AFP