BEIRUT (AP) — Activists say Syrian rebels have captured a hydroelectric dam on the Euphrates river in the country’s north in a strategic victory that followed days of fighting.

The Britain-based Syrian Observatory for Human Rights says the Tishrin Dam, near the town of Manbij, fell to the rebels before dawn on Monday.

Rami Abdul-Rahman, who heads the Observatory, says the dam supplies several areas of Syria with electricity.

The rebels have been making strategic advances recently. On Sunday, they briefly captured a regime helicopter base outside Damascus.

Syria’s conflict started in March 2011 as uprising against President Bashar Assad’s regime, inspired by other Arab Spring revolts.

It quickly morphed into a civil war that has since killed more than 40,000 people, according to activists.