Yemeni tribesmen blew up the country \'s main oil export pipeline in the northeastern province of Marib on Thursday, the second attack on the crude line in less than a week, Interior Ministry officials said. The attack occurred in Serwah district in Marib, quickly engulfing the crude in flames and forcing the petroleum installation to halt the export terminal port of Ras Esa in the Red Sea province of al-Hodayda. The incident \"came simultaneously with the assassination of an intelligence officer this morning in the province\'s central city, which bears the same name of Marib,\" an official told Xinhua by phone on condition of anonymity. On Sunday, the pipeline was exploded in the nearby area of Damashka, and the government also put the blame on tribal saboteurs. \"Tribal dignitaries managed today (Thursday) to secure the oil engineers to Damashka to repair the damages of the Sunday attack,\" the official said. The pipeline carries about 110,000 barrels of crude oil per day from Marib province to the export terminal on the Red Sea. Yemen\'s oil and gas pipelines, as well as its main electricity grid, have been frequently attacked since the eruption of protests against former President Ali Abdullah Saleh in 2011. Oil revenues make up more than 70 percent of the state budget, while oil and gas products account for over 90 percent of Yemen\'s exports.