BEIRUT — Syrian activists say rebels and government troops are fighting for control of a key airbase in the country’s north.

The Syrian Observatory for Human Rights says the rebels have launched a dawn offensive to take Taftanaz air base, a day before a crucial opposition conference in Qatar.

Taftanaz, which has been used by the Bashar Assad regime to launch attacks against rebel-held areas, lies near the highway between the capital Damascus and the northern city of Aleppo, a major front in the civil war.

Activist videos posted online claim to show the attack on Taftanaz. A rebel vehicle fires rockets and smoke rises over buildings and what appears to be an airstrip. The videos appear genuine and are consistent with other Associated Press reporting in the area.

Activists say more than 36,000 people have been killed in Syria since the uprising began in March 2011.