At least three rockets targeted the US embassy in Green Zone of Iraq capital Baghdad at dawn on Friday, landing on the outskirts of the district housing government and diplomatic buildings, an Iraqi security official said.
However, there was no immediate claim of responsibility of the incident, reports AFP.
A US military official speaking on condition of anonymity told AFP that alarms had gone off and that "likely impact sounds" could be heard near the US embassy and Union III base, where troops from the international anti-jihadist coalition are stationed.
This is the first reported attack against the United States embassy in the Iraqi capital since the Israel-Hamas war began in early October, raising regional tensions and fears of a wider conflict.
Since mid-October there have been dozens of rocket or drone strikes by pro-Iran groups against American or coalition forces elsewhere in Iraq as well as in Syria.
There are roughly 2,500 US troops in Iraq and about 900 in Syria as part of efforts to prevent a resurgence of the Islamic State group.
At around 4:20 am (0120 GMT), "three Katyusha rockets targeting the American embassy fell close to the Green Zone, near the river" Tigris, the Iraqi security official told AFP. The Iraqi official spoke on condition of anonymity as he was not authorised to speak to the media.
The US official said: "We are still awaiting official reports regarding casualties and damage to infrastructure, if any. We are also awaiting official reporting on the type of attack."
After the end of a seven-day pause in the war between Israel and Iran-backed Hamas last week, pro-Iran groups have resumed their attacks against American and coalition forces, justifying their actions by pointing to Washington's support for Israel.
Bd-pratidin English/Lutful Hoque
