Six rockets were fired Friday at the Iraqi capital’s airport, causing damage but no casualties, security sources said, the latest in a string of attacks the US blames on Iran-linked militias.

The rockets hit Baghdad International Airport’s runways or parking areas, one of the sources said.

“One civilian plane has been hit and damaged,” this source, based at the interior ministry, said.

A second security source confirmed the attack consisted of six rockets that fell around civil installations at the airport, damaging a stationary plane.

A third source identified the plane as a Boeing 767 belonging to the state-owned Iraqi Airways, noting that it was not in service and was undergoing repairs.

The attack was not immediately claimed.

Recent months have seen rocket and drone attacks target the US embassy in Baghdad’s high-security Green Zone, a US diplomatic facility at the airport and troops belonging to a US-led coalition stationed at Iraqi bases.

The attacks are rarely claimed but are routinely pinned on pro-Iran factions, who demand that US troops who were deployed to help Iraqi forces fight the Islamic State group leave the country.

The US-led coalition ended its combat mission in Iraq in December, four years after Iraq’s government declared victory over the jihadists.

But roughly 2,500 American soldiers and 1,000 coalition soldiers will remain deployed in Iraq to offer training, advice and assistance to national forces.

On January 3, US forces downed two armed drones that targeted the coalition at Baghdad airport, according to a coalition source.

On January 13, three people, including two children, were wounded by a rocket that hit a school in the Green Zone, while two other rockets fell inside the US embassy complex, without causing casualties.

In September, an “armed drone” attack targeted Arbil international airport in Iraqi Kurdistan, where a base hosts coalition troops.