Tribesmen bombed Yemen’s main oil export pipeline on Saturday, halting crude flows, local officials said, disrupting an important source of revenue for the impoverished state. Yemen’s oil and gas pipelines have repeatedly been sabotaged by insurgents or tribesmen since anti-government protests led to a power vacuum in 2011, causing fuel shortages and slashing export earnings for the country. The attack took place in the al-Habab area of the central oil-producing province of Maarib, and the tribesmen blew up the pipeline that carries crude from Safer oilfields to Ras Isa oil terminal on the Red Sea, the officials said. The Maarib pipeline carries around 70,000-110,000 barrels per day of Marib light crude. It was repaired in late May after a previous attack by tribesmen. Disgruntled tribesmen carry out such assaults to pressure the government to provide jobs, settle land disputes, or free relatives from prison. Frequent attacks on the crude pipeline cost Yemen around $400 million in lost revenue in the first quarter of 2014, the Interior Ministry said in May. Lawlessness in Yemen is also a global concern - particularly for the United States and its Gulf Arab allies - because of the country’s strategic position next to oil exporter Saudi Arabia and shipping lanes, and because is home to one of al Qaeda’s most active wings. Yemen is struggling to restore state authority after long-serving President Ali Abdullah Saleh was forced to step down in 2011. It relies on crude exports to bolster foreign currency reserves and finance up to 70 percent of government spending.