Iraq and the United States wrote letters to the UN Security Council on Sunday pledging to reach agreement on major operations by the US-led multinational force.The letters from PM Iyad Allawi and US Secretary of State Colin Powell, obtained by Reuters, opened the door for adoption as early as this week of a US-British draft resolution on Iraq’s future.A key unresolved issue in the council was Iraq’s role in important military actions. The letter will be attached to the resolution that would endorse an interim Iraqi government to take office on June 30 and authorise a US-led multinational force to ‘‘use all necessary means’’ to keep the peace.Allawi said he was setting up a new Ministerial Committee for National Security, in which the US command of a multinational force would participate. He said this group would need to ‘‘reach agreement of the full range of fundamental security and policy issues, including policy on sensitive offensive operations.’’ But the carefully-worded letters left unclear what would happen if the US military and Iraqis disagreed on a major offensive.Powell, in a separate letter, said the US command would ‘‘work to reach agreement on the full range of fundamental security and policy issues, including policy on sensitive offensive operations’’ with the Iraqis. Security Council members were called into a special session later on Sunday to discuss the letters. No vote has been scheduled. Members wanted to hear first from Lakhdar Brahimi, the UN envoy who helped form the interim government.