The international force would be led on the ground by several thousand Malian and West African troops but would receive extensive support from the Pentagon and the State Department, which would help train, equip and transport the troops, Obama administration officials said.

U.S. officials said the Pentagon’s planning efforts are contingent on the U.N. Security Council’s endorsement of the African-led force. U.N. officials and diplomats from other countries have said that U.N. approval is likely and that the military operation could begin next year.