Iran retaliated against the U.S. on Monday, launching missiles at a U.S. base in Qatar, according to a statement from the Qatar foreign ministry. The missiles targeted Al-Ubaid Air Base outside Doha and were intercepted by air defenses before they could strike the base, the Qatari government said.

The Pentagon already had begun taking measures to strengthen its firepower in the Middle East and protect U.S. bases there.

Iran launched a missile attack on Al Udeid Air Base — the largest U.S. military installation in the Middle East, which President Donald Trump visited just last month — after the U.S. carried out a series of bombings against three nuclear sites in Iran over the weekend.