Rebels have seized control of a strategic dam on the Euphrates river in northern Syria after days of fierce fighting, activists and a watchdog said on Monday.
Videos posted on the Internet show about a dozen rebel fighters in military fatigues walking at night on a road crossing the Tishreen dam, which straddles Aleppo and Raqa provinces, with others inside a control room, as one man proclaims: "The Tishreen dam is under Free Syrian Army control."
The authenticity of the videos could not be confirmed but the Syrian Observatory for Human Rights, which receives information from a network of activists and medics on the ground, confirmed the dam had fallen to the rebels.
"Rebels have taken control of the Tishreen dam and surrounding buildings in Aleppo province after fighters from several battalions stormed the area on Sunday," the Britain-based Observatory said.
The strategic advance came after several days of clashes and a siege of the dam by the insurgents, with the military responding with air strikes, according to the watchdog.
In one of the videos, rebels are seen milling inside a room containing an enormous control board of buttons and dials.
"Control room of the Tishreen dam," a man says from behind the camera. Outside the window, the dam can be seen in daylight.
Two rebels casually rest their Kalashnikovs on the tiled floor and watch as a man in civilian clothing works in front of five computer monitors. An older man in a wool sweater serves tea: "The employees, the engineer," the cameraman says.
Opposition fighters had already seized control of one of the main routes to Raqa, with the Tishrin dam giving them a second passage, while also connecting a wide expanse of territory between the two provinces bordering Turkey.
The Observatory also reported that Syrian troops on Monday pressed an assault on rebel strongholds in the northeastern outskirts of Damascus, killing a boy and girl from the same family in shelling attacks on the town of Irbin.
Elsewhere, fighting erupted along the ceasefire line of the Golan Heights, with two rebels killed in the villages of Al-Buraykah and Bir Ajam, both of which lie within the Syrian section of the demilitarised zone, the watchdog said.
The Israeli military earlier reported that gunfire on Sunday night from Syria hit the Israeli-occupied Golan Heights close to an Israeli military vehicle monitoring the ceasefire line but causing no injuries.
A military spokeswoman said Israeli troops in the area had not returned fire as they have done on previous occasions.
Fears of a spillover of the conflict which has ravaged Syria for more than 20 months and left over 40,000 people dead, have widened as violence has spread to Syria's borders with Turkey, Lebanon, Jordan and Iraq.