France, Germany, Italy, Britain and the U.S. vowed Friday to support the Iraqi government's investigation into a drone attack at Irbil airport Wednesday.
"We, the governments of France, Germany, Italy, the United Kingdom, and the United States of America condemn in the strongest terms the April 14 attacks in the Iraqi Kurdistan Region," said a joint statement issued by the State Department.
The statement added that the five countries will support the investigation to "ensure that those responsible will be held accountable."
"We are united in our view that attacks on U.S. and coalition personnel and facilities will not be tolerated and reiterate our steadfast commitment to the fight against ISIS."
An unmanned drone dropped explosives on a military base housing U.S. forces at the airport in Irbil, the capital of Iraq's Kurdistan region, Wednesday night.
"A drone charged with TNT targeted a coalition base at Irbil's airport," the Kurdish interior ministry said.
It added that there were no reported casualties, but a building was damaged.
Wednesday's attack was the first known attack carried out by an unmanned aerial drone against U.S. forces in Irbil.
There have been several rocket attacks on bases with U.S. forces and on the U.S. Embassy in Baghdad that Washington blames on Iran-backed militias.
There was no immediate claim of responsibility for the attack.