A memorandum of understanding ostensibly delineating maritime borders betwen Turkey and Libya causes “serious concern,” the European Union's new chief diplomat, Josep Borrell, said on Monday, after a meeting of the bloc's foreign ministers in Brussels.

The MoU, endorsed by the Turkish parliament last week, has fueled tensions between Turkey and Greece, Cyprus and Egypt over oil and gas drilling rights in the Eastern Mediterranean.

Last week, Greece expelled the Libyan ambassador for failing to divulge the contents of the deal.

"It is clear that this document is a cause of serious concern. We express our solidarity and our support to Greece and Cyprus,” the top EU diplomat said during a press conference he gave after the meeting.

Borrell also said it was clear the MoU is “problematic” for Greece and Cyprus and that it could cause problems for Greek islands. He said EU authorities are “examining it.”

Speaking to journalists before the meeting, he clarified that no sanctions would be discussed on Monday. “We just look at what this memorandum means and discuss about the content.”

“I do not expect an agreement on Libya. We expect to have a position after analysing which is the content of the memorandum of understanding, which has been kept not secret but unknown until a few days ago.”