WASHINGTON, Jan. 15 (Xinhua) -- The U.S. State Department confirmed on Tuesday that one American was killed in a deadly attack in the Kenyan capital of Nairobi earlier in the day.

"We can confirm that a U.S. citizen was killed in the attack," said a State Department official in an email responding to Xinhua's inquiry.

The official did not provide any further comment.

Al-Shabab terrorists struck an upmarket hotel and office complex in Nairobi on Tuesday, killing at least six people and injuring several others.

The attackers were armed with rifles and grenades. Huge explosions followed by gun shots rent the air as they stormed the complex.

UN Secretary-General Antonio Guterres later condemned the "terrorist attack" in a statement.