An unmanned drone dropped explosives on a base belonging to Iran-backed paramilitary forces in northern Iraq early Friday, The Associated Press reports.
Iraqi security officials and a military statement said two people were injured in the attack.
The statement said the drone dropped two grenades half an hour apart on the base in Amirli, in Iraq's northern Salaheddin province.
No further details were provided.
There was no immediate claim of responsibility for the attack, which struck shortly after midnight. The Iranian-backed mostly Shiite Muslim militias, in a statement, blamed the Islamic State (ISIS) group, saying it confronted the attack without providing details.
A senior official with the militias known collectively as the Popular Mobilization Forces told APthat the attack resulted in the wounding of two Iranians and that the base hit housed advisers from Iran and Lebanon.
He said the first attack targeted the headquarters of the advisers, resulting in the wounding of the two Iranians.
The second attack hit a weapons depot, causing a large fire at the base. The official spoke on condition of anonymity to disclose sensitive information.
An Iraqi official said ISIS were most likely behind the attack, ruling out a US-led coalition or American attack. He spoke on condition of anonymity in line with regulations.
Meanwhile, an Iraqi Shiite militia affiliated with Hezbollah said the attack carries the characteristics of Israel and the United States.
Though the attack comes at a time of increased tensions between the US and Iran, a Pentagon spokesman denied US involvement.
"We are aware of open source reports of possible aggressive actions against a Popular Mobilization Force unit in Salah ad Din. U.S. forces were not involved. We have no further information about this report," Navy Cmdr. Sean Robertson said.
Last month, Iran shot down a US drone, claiming it violated Iranian airspace near the Strait of Hormuz.
President Donald Trump approved military strikes against Iran in retaliation for the downing of the drone, but pulled back from launching them. He later made clear that he had not called off the planned strike on Iran but rather simply stopped it from going forward at that time.
A commander in Iran’s Revolutionary Guards then warned that US regional bases and its aircraft carriers in the Gulf are within the range of Iranian missiles.
