MOSUL, Iraq (Reuters) - Iraq's former Defense Minister Sultan Hashim Ahmed, number 27 on Washington's wanted list of former top officials under Saddam Hussein, has surrendered to U.S. forces, a mediator said on Friday. Dawood Bagistani, a local human rights official who has acted as go-between in talks with Ahmed, told Reuters the surrender would be officially announced later at a news conference in the northern Iraqi city of Mosul.