Since the pipeline was to pass through Afghanistan, it was necessary to work with the Taliban. The U.S. ambassador to Pakistan, Robert Oakley, left his post and was hired by CentGas in 1997. In January 1998, the Taliban, selecting CentGas over Argentinian competitor Bridas Corporation, signed an agreement that allowed the proposed project to proceed. In June 1998, Russian Gazprom relinquished its 10% stake in the project. On 7 August 1998, American embassies in Nairobi and Dar es Salaam were bombed. The United States alleged that Osama bin Laden was behind those attacks, and all pipeline negotiations halted, as the Taliban's then leader, Mullah Omar, announced that bin Laden had the Taliban's support. Unocal withdrew from the consortium on 8 December 1998, and soon after closed its offices in Afghanistan and Pakistan.