The United States remains "deeply concerned" about Turkey's actions in the Eastern Mediterranean, Secretary of State Mike Pompeo said Saturday, urging a diplomatic solution to the crisis.

Turkey in August sent an exploration ship and a small navy flotilla to conduct seismic research in disputed Mediterranean waters west of Cyprus, an operation that Greece condemned as illegal. Ankara and Athens both view the area as part of their continental shelf.

"Countries in the region need to resolve disagreements including on security and energy resource and maritime issues diplomatically and peacefully," Pompeo said in a fleeting trip to meet the Greek Cypriot administration's leader Nicos Anastasiades on Saturday night.

"Increased military tensions help no one but adversaries who would like to see division in transatlantic unity," he said.

Pompeo's trip comes shortly after the U.S. had lifted a decadesold arms embargo on the Greek Cypriot administration, outraging Turkey.

Previously Greek Prime Minister Kyriakos Mitsotakis announced a "robust" arms purchase program and an overhaul of the country's military, saying Turkey "threatens" Europe's eastern border and "undermines" regional security.

Athens has disputed Ankara's current energy exploration activities in the Eastern Mediterranean, trying to box in Turkish maritime territory based on small islands near the country's enormous coastline, the longest in the Eastern Mediterranean.

Ankara has sent out drillships to explore for energy on what it believes to be its continental shelf, saying that Turkey and the Turkish Republic of Northern Cyprus (TRNC) have rights in the region.