Azerbaijan said it was preparing to retaliate after two people were wounded on Thursday in Iranian drone hits on an airport and near a school.
"Azerbaijan is preparing the necessary retaliatory measures to protect the territorial integrity and sovereignty of our country and to ensure the safety of civilians and civilian infrastructure," the defence ministry said.
"These acts of attack will not go unanswered," it added.
Two drones crossed from Iran Thursday before one of them crashed into Nakhichevan's airport, the Azerbaijani news outlet Report said, without providing further details.
Video published on social media appeared to show smoke rising from the airport.
Iran's armed forces on Thursday denied having launched a drone attack on Azerbaijan.
"The Islamic republic of Iran... denies its armed forces launched a drone toward the Republic of Azerbaijan," the general staff of the armed forces said in a statement, according to state TV, which also blamed Israel.
"Such actions by the Zionist regime, aimed at disrupting relations between Muslim countries in various ways, are not unprecedented."
