Pakistan could pull back troops fighting Islamist militants near the Afghan border if the United States cuts off aid, the defense minister said on Tuesday in an interview with local media. The United States Monday said it would hold back $800 million -- a third of nearly $2 billion in security aid to Pakistan -- in a show of displeasure over Pakistan's removal of U.S. military trainers, limits on visas for U.S. personnel and other bilateral irritants. "If at all things become difficult, we will just get all our forces back," Defense Minister Ahmed Mukhtar said.