Clashes Friday between Yemeni soldiers who confronted armed tribesmen blocking access to a damaged oil pipeline killed four people in the central province of Maarib, sources said. The army attacked the tribesmen, who were preventing repair workers from reaching the pipeline blown up two weeks ago in the area of Wadi Abaydah, said the local and tribal sources. In the ensuing fighting, the army using shells and Katyusha-like rockets, and at least three tribesmen were killed, as well as an army colonel, the sources said. The 420-kilometre (260-mile) pipeline links the Safir oilfields to the Ras Issa terminal on the Red Sea, near the city of Hodeida. Attacks on oil and gas pipelines in Yemen are frequent, and Oil Minister Ahmad Dares said this week that sabotage had cost the country $4.75 billion (3.5 billion euros) between March 2011 and March 2013.