Defense Secretary Ash Carter arrived in Baghdad early Wednesday to meet troops and to talk with U.S. military commanders about the fight against ISIS.
The unannounced visit comes after Washington announced plans to deploy elite American military teams to Iraq to conduct raids against ISIS there and in neighboring Syria.
Carter was also due to meet with Iraqi Prime Minister Haider Abadi but a bad sandstorm was throwing his plans into doubt.
The U.S. is stepping up its military campaign against ISIS, which has claimed responsibility for attacks in the West, including bombings and shootings which killed 130 people in Paris last month.
