The attacks were claimed by a group calling themselves the Islamic Resistance, who said that two US soldiers were killed and six were wounded.
Centcom, the US military headquarters for the Middle East, told The National on Sunday that "the reports of alleged US service member deaths earlier today in Iraq are not true."
The attacks, an almost regular occurrence since the end of the US-led war on ISIS wound down in 2018, have spiked in the wake of the Israel-Gaza war.
Iran backs the Iraqi groups conducting the attacks, often militias in the state-linked Popular Mobilisation Forces. Some of the most powerful groups in the formation, including Kataib Hezbollah and the Badr Organisation have publicly warned the US and Israel over the escalating war in Gaza.
Analysts say the groups now announce attacks under the banner of the “Islamic Resistance in Iraq,” in contrast to the usual practice of announcing attacks on their own Telegram channels.
So-called Katyusha rockets on Sunday targeted the Ain Al Asad airbase, which hosts the Iraqi army, US and other international forces in western Iraq, and one blast was heard inside the base, two army sources said.
“Katyusha” rockets is a catch-all term for unguided Iran-made rockets such as the Fajr-1, which are based on Soviet-era designs.
On Saturday, defence systems at Ain Al Asad also reportedly intercepted and shot down two drones while they were hovering near the base, an attack later claimed by the Islamic Resistance.
“The drone came down inside the [Ain Al Assad] base” in the western province of Anbar, without causing any casualties or damage, a military source told AFP on condition of anonymity.
A statement issued on Telegram channels used by pro-Iranian armed groups said the attack was carried out by a group calling itself the Islamic Resistance in Iraq.
A second Iraqi security source told AFP the attack had involved two suicide drones. “The first was intercepted and the second crashed because of a technical problem,” the source said.
Since Wednesday, three Iraqi bases used by US-led coalition troops have been targeted in five separate attacks – Ain Al Assad, the Al Harir base in northern Iraq and a military camp near Baghdad airport.
The US currently has about 2,500 troops stationed at the three bases, alongside around 1,000 soldiers from other countries in the coalition set up to fight ISIS.
The attacks came after factions loyal to Iran stepped up threats against the US.
One of them, the Kataib Hezbollah, demanded that US forces “leave” Iraq, “otherwise they will taste the fires of hell”. The US killed the group's leader, Abu Mahdi Al Muhandis, alongside Iranian general Qassem Sulaimani, in a drone strike near Baghdad airport in 2020, in retaliation for Iran-backed attacks that killed a US contractor.
The assassination took Iran and the US to the brink of war, with Iran firing a salvo of ballistic missiles at US bases in Iraq, causing no fatalities but injuring scores of soldiers.