The attack was the first by Iranian-backed groups against US troops in Iraq since they halted a campaign in early February.
Several rockets have been fired from Iraq towards a US military base in northeastern Syria.
The attack, launched from the town of Zummar late on Sunday, was the first since early February to target US troops, when Iranian-backed groups in Iraq brought to an end a campaign that had seen regular strikes against the US-led international coalition.
The resumed hostilities came a day after Iraqi Prime Minister Mohammed Shia al-Sudani returned from a visit to the United States where he met with President Joe Biden.
A post on a Telegram group affiliated with Kataib Hezbollah said armed factions in Iraq had decided to resume attacks after a near-three month pause having seen little progress on talks to end the US-led military coalition in the country.
However, on Monday, Kataib Hezbollah said it had issued no statement claiming a return to attacks on US forces. It called the earlier announcement “fabricated news”.
A statement from the Iraqi security forces accused “outlaw elements of having targeted a base of the international coalition with rockets in the heart of Syrian territory”, at about 9:50pm (18:50 GMT).
Iraqi forces launched a major search operation in northern Nineveh province and found the vehicle used in the attack, the statement added.
‘Failed attack’
A US official, speaking on the condition of anonymity, told the Reuters news agency more than five rockets were fired from Iraq towards troops at a coalition base in Rmeilan, Syria, but no US personnel were injured.
The official referred to it as a “failed rocket attack”, but it was not immediately clear if the rockets had failed to hit the base or been destroyed before they reached. It was also not clear if the base was the target itself.
Following that, the official said, an aircraft from the US-led coalition in Iraq and Syria carried out a strike against the launch site.
Two security sources and a senior army officer in Iraq said a small truck with a rocket launcher fixed on the back had been parked in Zummar, a town on the border with Syria.
An army officer said the truck was destroyed and seized for further investigation.
“We are communicating with the coalition forces in Iraq to share information on this attack,” the officer added.
The targeting of US forces in the region intensified after the war in Gaza began on October 7.
In January, three US service members were killed and at least 34 others wounded in a drone attack in northeast Jordan near the Syrian border.