An attack Wednesday on an airport in Erbil, capital of Iraqi Kurdistan, was carried out by drone, the Kurdish interior ministry said, in an unprecedented escalation of the arms used to target US soldiers based there.
"A drone charged with TNT targeted a coalition base at Erbil's airport," the ministry said, adding that no one was hurt in the blast but a building was damaged.
A Turkish soldier was killed by rocket fire at around the same time at a military base 50 kilometers east in Bashiqa, Ankara said, but there was no immediate confirmation of any link between the two attacks.
"We strongly condemn tonight's terror attacks in Erbil and Bashiqa," the Kurdish region's premier Masrour Barzani said in a tweet after speaking with Turkish Foreign Minister Mevlut Cavusoglu.
"We agreed to stay in close contact as the investigation continues."
There was no immediate claim of responsibility for the airport drone attack, which caused an explosion heard across Erbil.
But a shadowy pro-Iranian group calling itself Awliyaa al-Dam (Guardians of Blood), which claimed responsibility for a similar attack at the airport in February, hailed the blast in pro-Tehran channels on the messaging app Telegram.
A security cordon blocked all access to the airport, witnesses reported. The governor said air links were not interrupted.
"Outraged by reports of attacks in the Iraqi Kurdistan Region," US State Department spokesman Ned Price said on Twitter.
"The Iraqi people have suffered for far too long from this kind of violence and violation of their sovereignty."
Some 20 bomb or rocket attacks have targeted bases housing American soldiers or diplomats in Iraq since US President Joe Biden took office at the end of January.
Dozens more took place over the preceding 18 months, with Washington consistently blaming pro-Iran factions.
"It seems the same militia who targeted the airport two months ago are at it again," Iraq's former foreign minister Hoshyar Zebari, a prominent Kurdish political figure, posted on Twitter in an allusion to pro-Iranian factions.
"This is a clear & dangerous escalation."
Pro-Iran groups have been ratcheting up their rhetoric, vowing to ramp up attacks to force out the "occupying" US forces, over a year after the Iraqi parliament voted to expel the American troops.
Counter-terrorism officials said only one rocket hit the airport on this occasion.
But an Iraqi security source told AFP that other rockets had crashed in the vicinity, including one targeting the Turkish troops.