Rockets were fired at the U.S. embassy in Baghdad on Friday in an attack believed to have been carried out by Iran-aligned militias which have targeted U.S. interests in Syria and Iraq over Washington's backing of Israel in the Gaza war.

No group claimed responsibility for the attack, which an embassy spokesperson said did not result in any casualties. State media said the headquarters of an Iraqi security agency were damaged.

Explosions were heard near the embassy, in the center of the capital, at about 4 a.m. on Friday. Sirens calling on people to take cover were activated.

It marked the first time the U.S. embassy had been fired on, apparently widening the range of targets after dozens of attacks on military bases housing U.S.forces in Iraq and Syria since mid-October, amid fears of broadening conflict in the region.

Sheikh Ali Damoush, a senior official in the Lebanese group Hezbollah, said in a Friday sermon that attacks by Iran-aligned groups across the Middle East aim to apply pressure to halt Israel's offensive in the Gaza Strip. He did not refer specifically to Friday's attack.

The dozens of attacks against U.S. forces in Iraq and Syria have been claimed by a group of Iran-aligned Shi'ite Muslim militias operating under the banner of the Islamic Resistance in Iraq.

The U.S. has responded with a series of strikes that have killed at least 15 militants in Iraq and up to seven in Syria.

'Acts of Terrrorism'

The attacks pose a challenge for Iraqi Prime Minister Mohammed Shia al-Sudani, who has pledged to protect foreign missions and capitlize on fragile stability to focus on the economy and court foreign investment, including from the United States.

Sudani directed security agencies to pursue the perpetrators, describing them as "unruly, lawless groups that do not in any way represent the will of the Iraqi people," a statement from his office said.

He also said that undermining Iraq's stability and reputation, and targeting places Iraq has committed to protect, were acts of terrorism.

The U.S. embassy spokesperson called on the Iraqi government to do everything in its power to protect diplomatic and coalition personnel and facilities.

"We reiterate that we reserve the right to self-defense and to protect our personnel anywhere in the world," he said.

Aside from its diplomatic staff in Iraq, the United States has about 2,500 troops in the country on a mission it says aims to advise and assist local forces trying to prevent a resurgence of the Islamic State.

Iran-aligned Houthis have been firing at Israel and at ships in the Red Sea in a campaign they say aims to support the Palestinians. U.S. warships have shot down several of their projectiles.