Rewards of $5 million each are being offered for Alhai Alhassan Haj Hamad and Mohamed Makawi Ibrahim Mohamed. The two were among five men convicted in a Sudanese court for the 2008 New Year's Day killing of U.S. diplomat John Michael Granville and his driver, Abdelrahman Abbas Rahama, in Sudan's capital, Khartoum.
At the time of their death, both Granville and Rahama were working for the U.S. Agency for International Development.
On Tuesday, the State Department formally designated Hamad and Mohamed as terrorists, a move that freezes any U.S. assets or property the men may have. The move also prohibits Americans from engaging in transactions with them.