MOGADISHU — The highest ranking U.S. official to visit Somalia's capital in years landed in Mogadishu on Sunday in another sign of improving security in the Horn of Africa's most chaotic nation.

Johnnie Carson, the assistant secretary of state for African affairs, arrived at the seaside airport Sunday morning, said Lt. Col. Paddy Ankunda, the spokesman for the African Union military force in Somalia.

A U.S. Embassy spokesman in neighboring Kenya said he could not comment. However, Carson is scheduled to speak at a news conference in Nairobi Kenya's capital later Sunday.

African Union troops pushed al-Shabab fighters out of the capital in August, allowing markets and even the arts to flourish for the first time in years. The U.N.'s top official visited in December the first visit by the U.N. secretary-general in nearly two decades.

The U.S. does not have an embassy in Somalia, though embassy officials from neighboring Kenya have visited Somalia in recent months and years. The last senior U.S. government official to visit Mogadishu appears to have been a visit by Gen. Anthony Zinni in 1997.