Salvoes of rockets were launched Friday at the US embassy in Baghdad's heavily fortified Green Zone, the mission said, the latest in a flurry of such attacks amid the Israel-Hamas war.
"A multi-rocket attack was launched at US and Coalition forces in the vicinity of Union III and the Baghdad embassy complex" without causing any reported casualties or damage, a US official said.
There was no immediate claim of responsibility.
The United States leads an international coalition battling jihadists in Iraq and neighbouring Syria, and its forces have come under repeated attack in recent weeks.
The attacks come against the backdrop of the more than two-month war between US ally Israel and the Iran-backed Palestinian Islamist militant group Hamas in the Gaza Strip.
In a statement, the US embassy said "two salvoes of rockets" were fired at the mission compound at around 4:15 am (0115 GMT).
"Indications are the attacks were initiated by Iran-aligned militias," said a US spokesperson.
The spokesperson called on Iraq's government to protect diplomats, coalition partners and facilities, adding: "We reiterate that we reserve the right to self-defence and to protect our personnel anywhere in the world."
Iraqi Prime Minister Mohammed Shia al-Sudani warned that attacks on embassies undermine the country's security and called on security forces to bring those responsible to justice.
Since mid-October there have been dozens of rocket or drone strikes by pro-Iran groups against US or coalition forces in Iraq as well as in Syria.
But Friday's rocket attack was the first against the US embassy in Baghdad since the Israel-Hamas war began on October 7, raising regional tensions and fears of a wider conflict.
An Iraqi security official said "three Katyusha rockets targeting the American embassy fell close to the Green Zone", near the river Tigris.
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.
- Around 80 attacks -
After the end of a seven-day pause in the war between Israel and Iran-backed Hamas last week, pro-Iran groups resumed their attacks against US and coalition forces, justifying their actions by pointing to American support for Israel.
In Iraq, most were claimed by the Islamic Resistance in Iraq, a loose formation of armed groups affiliated with the Hashed al-Shaabi coalition of former paramilitaries who are now integrated into Iraq's regular armed forces.
US forces have struck Iran-linked targets in both Iraq and Syria in response.
Sudani said Friday's attacks were "unacceptable and unjustifiable".
"Our security forces... will continue to protect embassies," the Iraqi premier said.
His foreign affairs adviser, Farhad Alaaldin, said the government was "determined" to uphold Iraq's stability.
"No attempt to destabilise the country will be tolerated," he added.
The UN Assistance Mission for Iraq also condemned the attack and warned of repercussions.
"Iraq cannot afford to be drawn into a wider conflict, which would threaten hard-won stability and the achievements made so far," UNAMI said on X, formerly Twitter.
On Sunday a US military official said a "self-defence strike" was carried out in northern Iraq against a drone launch site in the vicinity of Kirkuk.
The Islamic Resistance in Iraq later announced the death of "five martyrs".
On Wednesday, a US military official said a drone had targeted Western troops at the Ain al-Asad Airbase in western Iraq, but there were no casualties or damage.
Washington has counted at least 78 attacks since October 17 against its forces in Iraq and Syria.
The Israel-Hamas war began when Hamas gunmen attacked Israel on October 7, killing about 1,200 people, mostly civilians, and taking around 240 hostages, Israeli officials say.
In response, Israel vowed to destroy Hamas and launched a massive military offensive that has killed 17,177 people in Gaza, according to the territory's Hamas government.
The attacks against US personnel included rocket fire and drone strikes, and have left at least 60 US personnel wounded, the Pentagon says.