A drone strike hit Britain's Royal Air Force base of Akrotiri in Cyprus overnight, causing limited damage and no casualties, the island's president and Britain's defence ministry said on Monday.
The first attack on the British military facility since a rocket attack by Libyan militants in 1986, the incident represents a marked escalation in the conflict.
"All the competent services of the republic are on alert and in full operational readiness," President Nikos Christodoulides said in a speech.
The Shahed-type unmanned aerial vehicle caused minor damage when it crashed into the military facilities at 12:03am, he added.
"I want to be clear: Our country does not participate in any way and does not intend to be part of any military operation," Christodoulides said.
It was not immediately clear from where the Iranian-made Shahed had been fired. Two sources, speaking on condition of anonymity, told Reuters the British bases intercepted a second drone.
While the bases are regarded as British sovereign territory, Cyprus itself is an EU member, now holding the bloc's rotating presidency.
Akrotiri, south-west of the sprawling coastal city of Limassol, is one of two bases Britain has retained in the former colony since independence in 1960. In addition to the military facilities, it houses families of serving personnel.
Base authorities advised residents near Akrotiri to shelter in place until further notice after a "suspected drone impact", and added later that non-essential personnel would be dispersed, while other British facilities would operate normally.
Akrotiri, located on a square-shaped peninsula on the southern tip of Cyprus, has been used in the past for military operations in Iraq, Syria and Yemen.
On Sunday, Prime Minister Keir Starmer said Britain had accepted a US request to use its bases for defensive strikes against Iranian missiles in storage depots or launchers.
