Syrian rebels battle Assad's troops near Damascus

This image taken from video obtained from Ugarit News, which has been authenticated based on its contents and other AP reporting, shows Syrian rebels preparing to fire a rocket at Mannagh air base in Aleppo province, Syria, Monday, May 13, 2013. The Syrian government wants more details before deciding whether to take part in a proposed U.S.-Russian initiative to negotiate a peaceful end to Syria's crisis, the country's information minister said, staking out a similar position to the main opposition group.(AP Photo/Ugarit News via AP video)

BEIRUT (AP) — Activists say Syrian rebels and Islamic fighters have joined forces in a push to reopen an arms supply route and retake a key town near Damascus that fell back to President Bashar Assad's troops last month.

The Britain-based Syrian Observatory for Human Rights says Islamic units, including the al-Qaida-linked Jabhat al-Nusra, and Syrian opposition fighters are battling around the town of Otaybah, east of the capital.

The army regained control of Otaybah in late April, cutting an arms route for rebels trying to topple Assad's regime.

The Observatory said Wednesday that at least 23 rebel groups and Islamic fighter units that operated individually have joined the push to take back Otaybah and reverse government gains there.

More than 70,000 people have been killed since the revolt began in March 2011.