Tribal gunmen have bombed an oil export pipeline in the Yemeni province of Marib. Sources told Arabstoday that militants were responsible for blowing up the pipeline that carries Yemeni crude oil from production fields in Safer to Ras Isa port on the Red Sea in western Yemen.. The Yemeni Interior Ministry has named two defendants who have been involved in similar incidents to blow up the oil pipeline. The latest incident on Friday, is the sixth attack on the oil pipeline in a month. In the past two years, oil and gas exports from Yemen have been stopped because of repeated bombings by tribal gunmen.