US Secretary of State Mike Pompeo began talks on Monday in Greece to de-escalate tension in the eastern Mediterranean and boost tentative steps at dialogue between Athens and Ankara.

Pompeo began his two-day visit by meeting Greek counterpart Nikos Dendias in Thessaloniki. Neither side has released a statement.

“Thrilled to be back in Greece, a vital US partner with whom we share a common strategic vision,” the secretary of state tweeted on Monday.

“The strength of our bilateral relationship is at an all-time high, and I’m looking forward to a productive visit.”

Ahead of the trip, a senior US official said Washington was keen to tamp down the tension, reduce the likelihood of “accidents or incidents” and for Greece and Turkey to complete an agreement.

The two NATO members are at loggerheads over energy exploration in disputed waters after Ankara stepped up hydrocarbon research in the sea.

The row has roped in other European powers, raising concern about a wider escalation.

But last week Athens and Ankara said they were ready to start talks.

“Let’s meet, let’s talk and let’s seek a mutually acceptable solution. Let’s give diplomacy a chance,” Mitsotakis said on Friday to Turkish President Recep Tayyip Erdogan, in an address to the virtual UN General Assembly.

Pompeo will fly to the Greek island of Crete on Tuesday and tour the NATO naval base of Souda Bay.

Mitsotakis — who is hosting Pompeo at his family home on Crete — wants closer military ties with the US.

The secretary of state signed defence agreement last October allowing US forces a broader use of Greek military facilities.

A key element of the October deal was the northern Greek port of Alexandroupolis, a Balkans and Black Sea gateway of strategic value to the US navy and NATO.

The US has been granted priority status to the port after paying roughly $2.3 million (2 million euros) to remove a sunken dredging barge that had blocked part of the harbour since 2010.

At the time, Greek officials said the Pentagon was expected to invest over $14 million on the Greek airbase of Larissa and around six million euros at Marathi, part of the Souda base.

The visit to Thessaloniki is also intended as a sign to the Balkans on American willingness to invest in the region, the State Department said.

Pompeo will sign a bilateral science and technology agreement, and host an energy sector gathering of business leaders.

Pompeo’s tour later in the week also includes stops in Italy, the Vatican and Croatia.

In Rome, the secretary of state will discuss efforts by the Trump administration to deter its European allies from using equipment by Chinese manufacturer Huawei in developing their 5G networks.

The US accuses Huawei of being a tool for Chinese espionage.

Pompeo is also scheduled to attend a meeting at the Vatican on religious freedom, his human rights priority. There, too, he will warn of China’s actions against minorities, including Muslims.