Grappling with a record death toll in an overshadowed war, US President George W. Bush promised Wednesday to send more US troops into Afghanistan by year's end. He conceded that June was a "tough month" in the nearly 7-year-old war. In fact, it was the deadliest month for US troops in Afghanistan since the conflict began. "One reason why there have been more deaths is because our troops are taking the fight to a tough enemy, an enemy who doesn't like our presence there because they don't like the idea of America denying safe haven (to terrorists)," Bush told reporters. "Of course there's going to be resistance." Bush said it was a tough month too for the Taliban fighters. The former ruling Islamic militants have rebounded with deadly force since their overthrow 6 years ago by US-led troops.