An airstrike targeted fighters of the pro-government Hashd al-Shaabi militia (Popular Mobilization Forces) near the Iraqi-Syrian border, said an Iraqi army officer on Wednesday.
Two vehicles belonging to the Iraqi militia were struck by missiles in the city of al-Bukamal in eastern Syria, near the border with Iraq, the officer said on condition of anonymity because he was not authorized to brief the media.
There were reports of casualties in the attack.
Local sources in al-Bukamal told Anadolu Agency that the airstrike targeted Iranian-backed groups in the area.
It remains unclear what party was responsible for the airstrike.
A spokesman for the US-led coalition in Iraq denied it was the US that launched the airstrike.
The coalition "can confirm we did not conduct airstrikes in Al-Bukamal," Col. Wayne Marotto tweeted.
In recent years, Israel has been accused of attacks on positions of Iranian-backed groups in the border area between Iraq and Syria, where Iranian-backed groups are active.
Hashd al-Shaabi is an Iraqi pro-government Shia force with a number of Iranian-aligned militias operating under its umbrella. It was officially announced in 2014 with the aim of fighting the terror group Daesh/ISIS.