WASHINGTON (AP) — A senior White House official says the U.S. remains focused on finding those responsible for the Sept. 11, 2012, attack on U.S. diplomatic facilities in Benghazi, Libya, that killed Ambassador Christopher Stevens and three other Americans.

Susan Rice said on NBC’s “Meet the Press” on Sunday that the U.S. has “made progress” in the search for the perpetrators, but she did not elaborate. She said U.S. officials are committed to pursuing it until they succeed.