ARBIL: An attack Wednesday at the airport of Arbil, capital of Iraqi Kurdistan, was carried out by drone, the Kurdish interior ministry said -- an unprecedented escalation of the arms used to target US soldiers based there.

"A drone charged with TNT targeted a coalition base at Arbil's airport," the ministry said, adding that no one was hurt in the blast but a building was damaged.

There was no immediate claim of responsibility for the attack, which caused a loud explosion audible across the city.

However, a shadowy pro-Iranian group, blamed for a similar attack in mid-February, hailed the blast in pro-Iran 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.

Some 20 bomb or rocket attacks have targeted bases housing US soldiers or diplomats in Iraq since US President Joe Biden took office at the end of January.

Dozens more took place during the preceding 18 months, with Washington consistently blaming pro-Iran armed factions.

Washington and Tehran are both allies of Baghdad, but remain sharply at odds over Iran's nuclear programme.

On February 15, more than a dozen rockets targeted a military complex inside Arbil airport, killing an Iraqi civilian and a foreign contractor working with US-led troops.

The complex hosts foreign troops deployed as part of a US-led coalition helping Iraq fight the Islamic State group, a fight that Baghdad declared as won in late 2017.

A shadowy group calling itself Awliyaa al-Dam (Guardians of Blood) claimed the February attack in Arbil and in a follow-up statement vowed to keep targeting US forces in Iraq.