U.S. president Barack Obama has said the country's mission in Afghanistan will shift to a support role in the spring and he will soon get recommendations from his top military advisers on U.S. troop reductions, Belfast Telegraph reported.

Obama said in a joint news conference with Afghan president Hamid Karzai that any withdrawal agreement must include an immunity agreement in which U.S. troops are not subjected to Afghan law.

Obama said the path of the U.S. military remained clear and the war was moving towards a "responsible end" in 2014.

The two leaders met at the White House on the future of the U.S. role in Afghanistan and the 66,000 American troops serving there.

The U.S. military mission will shift from combat to support in the spring, a few months ahead of schedule.