Washington, D.C. ? The violence that has surged for two years in Afghanistan reached a new high last week, and more difficulty lies ahead, the commander of U.S. troops in the Middle East said Thursday.

Gen. David Petraeus said the number of attacks in Afghanistan over the last week hit the highest level since the December 2001 fall of the Taliban.

“Some of this will go up because we are going to go after their sanctuaries and safe havens as we must,” Petraeus, in charge of the wars in Afghanistan and Iraq as leader of U.S. Central Command, said during a speech at the Washington think-tank Center for a New American Security.

“But there is no question the situation has deteriorated over the course of the past two years in particular and there are difficult times ahead,” he said.

There were more than 400 insurgent attacks last week, including ambushes, small arms volleys, assaults on Afghan infrastructure and government offices, and roadside bomb and mine explosions. In comparison, attacks in January 2004 were less than 50 per week.