US President Donald Trump has expressed concern about mounting tensions between Greece and Turkey in separate telephone conversations with the leaders of both countries.

According to the White House, Trump urged the two NATO allies “to commit to a dialogue” about their dispute over the Eastern Mediterranean in a call with Greek Prime Minister Kyriakos Mitsotakis on Wednesday night.

“President Trump reaffirmed that Greece and Turkey must commit to dialogue, which is the only path to resolving their differences. The two leaders also discussed important bilateral and regional issues,” said White House Deputy Press Secretary Judd Deere.

The US president also spoke with Turkish President Recep Tayyip Erdogan, discussing “regional developments and tensions in Eastern Mediterranean,” the Turkish Directorate of Communications said early on Thursday.