The United States announced Tuesday that it would lift for one year its three-decade-old arms embargo on Cyprus to allow "non-lethal" military goods to be sold to the Mediterranean island.
In a move which drew an immediate rebuke from Turkey, Secretary of State Mike Pompeo informed Republic of Cyprus President Nicos Anastasiades of the change in a phone call Tuesday.
From October 1, the US will remove blocks for one year on the sale or transfer of "non-lethal defense articles and defense services."
Pompeo also "reaffirmed US support for a comprehensive settlement to reunify the island," said State Department spokesperson Morgan Ortagus.
The announcement came amid a surge in tensions in the eastern Mediterranean between Turkey and Greece over maritime borders and gas drilling rights, which also involves Athens-allied Cyprus.
Both Greece and Turkey staged naval drills in the area to assert their sovereign claims, and the European Union warned Ankara Friday to pull back or face EU sanctions.
The United States imposed the arms embargo in 1987, in the hope that it could encourage the reunification of the island, about one-third of which is controlled by Turkey since a 1974 invasion.
But the embargo was counter-productive, simply pushing the Cypriot government to create alliances with other countries without making progress on reunification.
Democratic Senator Bob Menendez said the move recognized the importance of the US relationship with Cyprus, which he called "a reliable strategic partner for our nation."
"It is in our national security interest to lift these outdated decades-long arms restrictions and deepen our security relationship with the Republic of Cyprus," he said in a statement.
The Turkish foreign ministry said the US move "poisons the peace and stability environment in the region" and does "not comply with the spirit of alliance" between the United States and Turkey.
If Washington does not reverse course, the ministry said, "Turkey, as a guarantor country, will take the necessary decisive counter steps to guarantee the security of the Turkish Cypriot people, in line with its legal and historical responsibilities."