DUBAI (Reuters) - Electricity supply was hit in Yemen on Friday after tribesmen attacked a main power plant, an official said, accusing them of acting on behalf of opposition parties demanding President Ali Abdullah Saleh resign.
The official said the tribesmen are blocking the road from Sanaa to Marib province, where the plant is located, preventing engineers arriving to restore full power.
The cities of Sanaa, Taiz, Hudaida and Ibb are suffering reduced electricity because of the attack.
Tribesmen in the impoverished Arabian Peninsula state often challenge central government over grievances.
Protesters have been camped out in Sanaa since early February demanding political reforms. Opposition parties, clerics and many tribal leaders are demanding that Saleh step down.
Saleh, who has lost control of several provinces, has warned of civil war and the break-up of Yemen if he is forced to step aside before organizing parliamentary and presidential elections over the next year.
(Reporting by Mohamed Sudam; Editing by Janet Lawrence)