U.S. President Barack Obama has nominated his ambassador to Kuwait, Matthew Tueller, to fill the open ambassadorship in Sanaa, Yemen, the White House said Thursday. A veteran diplomat, Tueller has been the U.S. ambassador to Kuwait since 2011. He has also held high-level ranking positions in U.S. embassies in Egypt, Iraq, Qatar, and Saudi Arabia. He worked previously in Yemen in 2000 and 2001.