Iran launched missiles at a US military base in Qatar on Monday, in what it said was retaliation for American strikes against its nuclear sites over the weekend. Witnesses reported hearing loud bangs in the sky above the capital, Doha, while videos showed bright flashes in the sky as air defence systems attempted to intercept missiles.

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

President Trump said Monday the Iranian government offered "early notice" about a series of missile strikes that targeted the U.S. Al Udeid Air Base in Qatar, downplaying Iran's response to the U.S. bombing of some Iranian nuclear sites over the weekend as "very weak."