German Foreign Minister Heiko Maas will hold talks in Greece and Turkey on Tuesday in a bid to help defuse mounting friction over gas reserves in the eastern Mediterranean.
The discovery of major natural gas deposits in waters surrounding Cyprus and the Greek island of Crete has triggered a scramble for energy riches and revived old regional rivalries.
The biggest tensions are between historically uneasy NATO allies Turkey and Greece, which almost went to war over some uninhabited islets in the Aegean Sea in 1996.
Germany has sought to mediate in the conflict, while fellow EU heavyweight France has taken a tougher line against Ankara, sending warships to help Greece in the standoff.
A German foreign ministry spokesman, Christofer Burger, told reporters Monday that Haas would speak with his counterparts in Athens and then Ankara, with joint news conferences planned in both capitals.
In Greece, Maas will also meet Prime Minister Kyriakos Mitsotakis and Syriza party leader Alexis Tsipras.
"We take the tensions there very seriously," Burger said.
"We are worried that the tensions could further weigh on the relationship between Turkey and the EU and that further escalation could have grave consequences."
Germany currently holds the rotating presidency of the European Union.
Chancellor Angela Merkel's spokesman Steffen Seibert told the briefing that it was "essential" that Germany "remain in dialogue with both sides".
"The aim is for Greece and Turkey to resolve their problems with each other directly."
Last week, EU foreign ministers convened an emergency video conference after Greek and Turkish warships collided in hotly disputed circumstances.