WASHINGTON (Reuters) -The United States imposed sanctions on Monday on three former Sudanese officials for their role in undermining peace, security and stability in Sudan, the Treasury Department said. The sanctions are being imposed under a U.S. executive order that places penalties on people who destabilize Sudan and undermine democracy, the department said in a statement. It named the three as Taha Osman Ahmed al-Hussein, Salah Abdallah Mohamed Salah and Mohamed Etta Elmoula Abbas, all forme