Quetta, Pakistan -- Assailants torched more than 20 tankers in Pakistan carrying fuel for U.S. and NATO troops in neighboring Afghanistan on Thursday, in the first reported attack since Islamabad closed the border to protest coalition air strikes that killed 24 Pakistani troops last month.

Several hundred trucks have been stranded at poorly guarded terminals around the country as they wait for Pakistan to reopen its two border crossings into Afghanistan. Around 40 percent of the nonlethal supplies for U.S.-led troops in landlocked Afghanistan travel across Pakistani soil.