Armed factions close to Iran have threatened to attack US interests in Iraq over Washington's support for Israel since Hamas militants killed more than 1,400 people in a shock cross-border attack from Gaza on October 7.

Israel's retaliatory bombardment of Gaza has killed more than 4,100 people, according to its Hamas-controlled health ministry.

"We can confirm a rocket attack on US and coalition forces at the Baghdad diplomatic support centre, near the Baghdad international airport, occurred Friday at approximately 2:50 am" (2350 GMT Thursday), a Pentagon official said.

"Initial assessments indicate two rockets were fired. One was intercepted by a counter-rocket system and the other impacted an empty storage facility. There were no casualties reported," the official said, speaking on condition of anonymity.

An Iraqi security official had earlier told AFP that three Katyusha rockets struck near a base of the international coalition close to Baghdad airport.

An Iraqi military source said there were no casualties in the attack and material damage was "being assessed".

There was no immediate claim of responsibility for the attack.

On Thursday evening, another rocket attack targeted the Ain al-Assad base in western Iraq, where US forces are also stationed, an Iraqi military source said.

"No damage" was reported, he said of the second attack that was claimed by a group called "Islamic Resistance in Iraq" on Telegram channels affiliated with Shiite factions loyal to Iran.

On Wednesday, the US military said it shot down two drones which fired on US and coalition forces in western Iraq.

The United States currently has about 2,500 troops stationed at three bases in Iraq, alongside around 1,000 soldiers from other countries in the coalition set up to fight the Islamic State jihadist group.

The attacks came after factions loyal to Iran stepped up threats against the United States.

One of them, the Hezbollah Brigades, demanded that US forces "leave" Iraq, "otherwise they will taste the fires of hell".