Azerbaijan warned that it would respond after drones believed to have come from Iran struck its exclave of Nakhchivan on Thursday, injuring two people and damaging buildings, officials said.

Azerbaijan’s Foreign Ministry said it summoned Iran’s ambassador in Baku to deliver a formal protest, calling the incident a violation of international law and warning that the country reserves the right to take “appropriate measures.”

Officials said one drone hit the terminal area of Nakhchivan International Airport, located close to the Iranian border. Another drone came down near a school in a nearby village, causing additional damage.