Attackers armed with machineguns and rocket-propelled grenades have struck Yemeni government targets in the Maarib region and clashed with security forces.
In a series of night-time raids on Thursday, the gang attacked a government building in Maarib city, a power station and police checkpoints in the area, reports said.
Al Jazeera's correspondent in Yemen reported that an attack by rocket-propelled grenades on the electricity power station led to an outage in the entire eastern city, around 150km east of the Yemeni capital Sanaa.
It is not yet known if anyone was killed or injured in the attacks, which occurred a day after security forces killed four fighters in the area.
Witnesses reported a heavy police presence in Maarib and the surrounding area following the attacks, although there has so far been no confirmation from Yemeni officials.