ATHENS, Greece — The U.S. is looking at further expanding its military presence in Greece, including increasing access for U.S. aircraft and ships, and increasing joint exercises there, Chairman of the Joint Chiefs Gen. Joseph Dunford said Tuesday.

“If you look at geography, and you look at current operations in Libya, and you look at current operations in Syria, you look at potential other operations in the eastern Mediterranean, the geography of Greece and the opportunities here are pretty significant,” Dunford said.

U.S. officials who briefed reporters traveling with Dunford said no specific bases have been identified, but that Supreme Allied Commander Europe Army Gen. Curtis Scaparrotti is evaluating several options for increased U.S. flight training, port calls to do forward-based ship repairs and additional multilateral exercises. “Those are discussions that Gen. Scap and others are having right now, as they look around the region in terms of where they want to put forces” within the next five to 10 years, one official said.

The welcome mat for an expanded U.S. presence comes as Greece faces increasing uncertainty over its relationships with Russia and Turkey, the official said.

Greece has “been looking around this neighborhood and recognizing the same instability ... that we have" the official said. “They’ve always had a nervousness about their NATO ally Turkey.”

Dunford said an increased use of Greek bases was not tied to U.S. relations with Turkey, and that the U.S. expects that its use of Incirlik Air Base will continue.

However, U.S.-Turkey relations have deteriorated significantly over the last several years over disagreements about U.S. policy in Syria, the 2016 failed coup in Turkey and Turkey’s pursuit of Russia’s S-400 missile defense system.

This month lawyers for the Turkish government have sought to halt U.S. flights departing Incirlik, as they pursue U.S. Air Force officers they allege were connected to the 2016 coup attempt.

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Discussions of an expansion come amid a surge in U.S. use of Greek ports and military bases. This spring the U.S. began operating unarmed MQ-9 Reaper drones out of Greece’s Larisa Air Force Base. The transport dock ship New York has made two recent port calls, and the aircraft carrier Truman made a port call in May. The officials said U.S. naval and air presence at Souda Bay “in some respects is at capacity now, in terms of its support for EUCOM, for AFRICOM, for TRANSCOM, even SOCOM now" in part due to increased traffic in support of operations in Syria.

“We have taken advantage of Souda Bay,” Dunford said. “It’s a critical piece of infrastructure here, in the region.”

Dunford said the U.S. is not looking for a new, permanent base, but has discussed additional options for transiting military or additional multilateral exercises.

Despite its own economic crisis, Greece has also continued to spend 2 percent of its GDP on defense, including signing a $1.5 billion contract with the U.S. to upgrade the avionics in 85 of its 129 F-16 fighter jets, the officials said.

The agreement was signed in the spring, with the final details expected to be completed this fall. Greece is also set to receive 70 OH-58 U.S. Army Kiowa helicopters through the U.S. excess defense articles program and has contracted to upgrade four of its P-3 Orion reconnaissance aircraft, the officials said.