KABUL, Afghanistan — President Hamid Karzai insisted Thursday that the United States confine its troops to major bases in Afghanistan by next year as the Taliban announced that they were suspending peace talks with the Americans, both of which served to complicate the Obama administration’s plans for an orderly exit from the country.

Mr. Karzai’s abrupt planning shift was at odds with a pledge offered just hours earlier by President Obama to stick to a 2014 withdrawal schedule for troops in Afghanistan. It also ran up against the Pentagon’s stark assessment that Afghan security forces were not yet ready to take over control of the country.

Mr. Karzai’s surprise announcement, which would confine American troops to their bases a year earlier than Mr. Obama proposed, was initially made at a Thursday meeting with Defense Secretary Leon E. Panetta, who spent a fraught two days here apologizing in person to the Afghan president for the massacre of civilians by an American soldier last Sunday at a village in Kandahar Province. Upon Mr. Panetta’s arrival, an Afghan interpreter working for coalition forces crashed a stolen pickup truck near his plane.

Further fraying the United States’ efforts to preserve some degree of control over its exit strategy from Afghanistan, Taliban insurgents announced Thursday that they had broken off preliminary peace talks with the Americans. While the move may have been coincidental, it imperiled another crucial element of the American exit strategy in Afghanistan — brokering peace talks between insurgents and the government.