The EU on Friday warned Turkey it could face fresh sanctions -- including tough economic measures -- unless progress is made in reducing soaring tensions with Greece and Cyprus in the eastern Mediterranean.
EU diplomatic chief Josep Borell said the bloc wanted to give "a serious chance to dialogue" but was steadfast in its support for member states Greece and Cyprus in the crisis, which has raised fears of a military standoff.
A dispute over maritime borders and gas drilling rights has reignited the long-running rivalry between Athens and Ankara, with the two neighbours staging rival naval drills.
EU foreign ministers meeting for talks in Berlin agreed to a request from Cyprus to sanction more individuals for their role in Turkey's exploratory drilling in waters claimed by the island.
Borrell urged Ankara to "abstain from unilateral actions" as a basic condition to allow dialogue -- which Germany is trying to broker -- to advance.
"We agreed that in the absence of progress in engaging Turkey we could develop a list of further restrictive measures that could be discussed at the European Council on September 24 and 25," Borrell said after the talks.
Asked what these measures might entail, Borrell said sanctions could be extended to ships or other assets involved in the drilling, as well as prohibting the use of EU ports and supplies and restricting "economic and financial infastructure related with this activity".
Wide-ranging sanctions against whole sectors of the Turkish economy could also be considered, he said, but indicated these might only come into play if more targeted measures against the drilling were not effective.