Several blasts hit a US-led coalition military base in Baghdad early on Sunday from an apparent rocket attack, a US military official said.
The official did not immediately say if the attack caused any casualties or significant damage.
This is the 19th attack against US assets in the country since late October.
The blasts were followed by aircraft circling over the Green Zone.
Earlier, Al Arabiya correspondent reported strong explosions near the vicinity of the US embassy in Baghdad’s heavily fortified Green Zone.
The explosion sent warning sirens blaring across the high-security diplomatic compound.
The attacks are never claimed but the US has pointed the finger at Iran-backed groups within the Hashed al-Shaabi, a military network officially incorporated into Iraq’s state security forces.
In late December, a rocket attack on the northern Iraqi base of K1 left one US contractor dead and unleashed a dramatic series of events.
Washington responded with retaliatory strikes against a hardline Hashed faction in western Iraq and days later, an American drone strike in Baghdad killed top Iranian general Qassem Soleimani and his right-hand man, Hashed deputy chief Abu Mahdi al-Muhandes.
Hashed factions have vowed revenge for the pair’s death, insisting US troops should immediately leave Iraq.
Sunday’s attack came just hours after one of the Hashed’s Iran-backed factions, Harakat al-Nujaba, announced a “countdown” to ousting American forces from the country.
(With Reuters, AFP)