ATHENS, Greece >> A Greek air force jet crashed into the Aegean Sea today, killing the pilot, as he returned from a mission to intercept Turkish aircraft that had violated the country’s air space, Greek officials said.

The Turkish government did not comment publicly about the accusations of an encounter. The state-run Anadolu news agency quoted unnamed military officials as disputing scattered reports that there had been a dogfight between jets from the two countries and denying that any Turkish air force jet had been in the area.

Greek officials said nothing about what might have caused the crash, or whether it was connected to a confrontation with Turkish jets, though they stressed that the crash occurred several kilometers from the site of the interception mission.

The Hellenic air force said it lost contact with its Mirage 2000-5 jet at 12:15 p.m., while the aircraft was about 10 miles northeast of Skyros, an island near the central Aegean. The pilot was identified as Capt. Giorgos Baltadoros, 33, a father of two children, and Defense Minister Panos Kammenos described him on Twitter as a “hero who fell defending national sovereignty and territorial integrity.”

An official at the Greek Defense Ministry said the jet was returning from a mission to intercept two Turkish F-16 jets farther east, near the Greek island of Lesbos.

“The mission had finished and it had been on its way back with another Greek plane,” said the official, who was not authorized to speak publicly.

Close encounters between Greek and Turkish aircraft are common in the Aegean, which is flanked by Greece to the west and Turkey to the east, and where the traditional foes have engaged in lingering territorial disputes, though such episodes are rare.

Air patrols in the Aegean and interceptions of Turkish aircraft that Greece considered to be in its air space have spiked in recent weeks, increasing friction between the neighbors, both members of NATO. Greece said its troops fired tracer rounds Monday night as a warning after a Turkish helicopter with its lights off flew close to the Greek islet of Ro in the southern Aegean. Turkey has not commented on the matter.

The conflicts have escalated at a time of high tension on Turkey’s southeastern flank, along its border with Syria. Turkey, Iran and Russia are deeply entwined in the complex civil war, Israel has struck at Syrian and Iranian targets, and the United States and its allies are weighing strikes against the Syrian government for suspected use of chemical weapons.

Turkey and Greece both claim sovereignty over two rocky islets in the Aegean, known as Imia in Greece and Kardak in Turkey. They nearly went to war over the islets in 1996, after a Turkish cargo ship ran aground, the two nations traded angry accusations, and both sent troops there. U.S. diplomats intervened to avert a military clash.

The recent increase in military activity in the Aegean comes amid a wave of unusually aggressive rhetoric between the two countries. In Greece, Turkish hostility is interpreted by many analysts as an attempt by President Recep Tayyip Erdogan to grandstand for his domestic audience.

Tensions have also dogged the relationship between Turkey and the European Union, of which Greece is a member. Turkey is technically still seeking membership in the bloc, but talks have ground to a halt as Erdogan’s government has become increasingly autocratic.

Turkey and the European Union reached an agreement in 2016 to contain the flow of migrants into Europe, but Erdogan has at times threatened to allow them through unimpeded. Migrant arrivals to the Greek islands from Turkey have increased sharply in recent days.

Other issues are straining ties between Athens and Ankara. Two Greek soldiers have been in a Turkish jail for nearly six weeks after crossing the border in bad weather, in what Greece has said was an accident. And eight Turkish soldiers who fled the 2016 coup in Turkey are seeking asylum in Greece, but Turkey is insisting that they be returned.

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