At least five rockets were launched from Iraq's town of Zummar towards a US military base in northeastern Syria on Sunday, two Iraqi security sources told Reuters.
The attack against US forces is the first since early February when Iranian-backed groups in Iraq stopped their attacks against US troops.
It comes 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 at the White House.
Rocket launchers fire at US forces
Iraq’s Kataib Hezbollah said early on Monday that armed groups decided to resume attacks on US forces in the country after seeing little progress on talks to achieve the exit of US troops during Iraq's prime minister's visit to Washington.
Kataib Hezbollah later denied these statements, saying they were fabricated. A statement on their Telegram stated that they were not resuming attacks on US forces.
“What happened a short while ago is the beginning,” the group said in an apparent reference to the attack late on Sunday.
Two security sources and a senior army officer said a small truck with a rocket launcher fixed on the back had been parked in Zummar, a town on the border with Syria.
The military official said the truck caught fire with an explosion from unfired rockets at the same time as warplanes were in the sky.
"We can't confirm that the truck was bombed by US warplanes unless we investigate it," said a military official on condition of anonymity because of the sensitivity of the incident.
Another army officer said the truck was seized for further investigation and initial investigation shows that it was destroyed by an air strike.
"We are communicating with the coalition forces in Iraq to share information on this attack," the officer added.
The Iraqi Security Media Cell, an official body responsible for disseminating security information, said in a statement that Iraqi forces had launched "a wide-ranging search and inspection operation" targeting the perpetrators near the Syrian border, pledging to bring them to justice.
The attacks came after a huge blast at a military base in Iraq early on Saturday killed a member of an Iraqi security force that includes Iran-backed groups. The force commander said it was an attack while the army said it was investigating and there were no warplanes in the sky at the time.
Coalition fighter destroyed launcher in self defense, no US personnel injured, official says
A coalition fighter destroyed a launcher in self defense after reports of a failed rocket attack near a coalition base in Syria, a US official said on Sunday, adding that no US personnel were injured.
The attack against US forces is the first since early February when Iranian-backed groups in Iraq stopped their attacks against US troops.
Reuters contributed to this report