Four fighters from the Iran-backed Kataeb Imam Ali group were killed in northern Iraq on Tuesday in air strikes blamed on the US, the armed faction announced.
The attacks followed the downing of a drone late Monday near the UAE embassy in the nearby city of Erbil, drawing condemnation from Arab countries.
The Kataeb Imam Ali group said its fighters were killed in "American aggression" against one of their positions in the Debs district of Kirkuk province, said AFP.
The bombing targeted a position belonging to the Hashed al-Shaabi, which is an alliance of factions now integrated into Iraq's regular army and includes powerful Iran-backed groups.
The Iraqi government's security information cell confirmed that several Hashed fighters were killed in a "bombing" in Kirkuk, without attributing the strike to anyone.
"It is a blatant attack on Iraq," it said.
Since the start of the Middle East war, bases belonging to Hashed al-Shaabi, or the Popular Mobilization Forces, have been hit several times, with strikes targeting pro-Iran fighters.
Iraq, long a proxy battleground between the US and Iran, had said it did not want to be dragged into the war, but it has not been spared.
It was drawn in from the outset, with strikes blamed on the United States and Israel targeting Iran-backed groups, which have since claimed attacks on US bases in Iraq and the wider region.
Drone and rocket attacks have targeted Baghdad International Airport, which houses a military base and a US diplomatic facility, as well as oil fields and facilities.
On Monday night, two drones were downed near the military base, a security source told AFP.
The northern autonomous Kurdistan region, of which Erbil is the capital, hosts US troops and has been a main target of drone attacks, but these have largely been intercepted.
Iran's Revolutionary Guards said Tuesday that they had targeted a US base in the region.
"The headquarters of the invading US army in Al-Harir Air Base in the Kurdistan region was targeted with five missiles," the Guards said in a statement.
Late on Monday, Kurdish counter-terrorism forces said US-led coalition forces had "downed three explosive-laden drones over Erbil".
One drone fell near the UAE consulate in the city, a statement added, with no casualties reported.
The Kurdistan regional government condemned the attack as "unjustified".
Saudi Arabia, Qatar and Jordan also criticized the targeting of the consulate.
A Kurdish security source told AFP late Monday that the drone was likely aimed at the US consulate but did not reach its target and fell instead near the Emirati mission.
