The U.S. has withdrawn a negotiating team from Pakistan after failing to reach a deal with the Pakistani government over the reopening of NATO supply lines for troops in Afghanistan. The apparent stalemate is the latest sign of rising tensions between Pakistan and the United States. Last week Defense Secretary Leon Panetta said the U.S. was losing patience with the Pakistani government over its failure to crack down on militants. Pakistan closed the supply routes to troops in Afghanistan after U.S. air strikes killed two dozen Pakistani soldiers last November. The U.S. has refused to apologize for the attacks. An unnamed U.S. official recently told the Associated Press the U.S.-Pakistan relationship is “the worst it has ever been.”