ATHENS, Greece (AP) — Greece's prime minister said Monday that Turkish fighter jets harassed the helicopter he was traveling on during a visit to a remote Greek island to celebrate Greece's independence day.

Alexis Tsipras said he was "welcomed" by Turkish fighter jets violating Greek airspace during his arrival Monday on the small eastern Aegean island of Agathonissi.

The move forced the helicopter pilot to carry out low maneuvers until Greek fighter jets arrived to deflect the Turkish aircraft, Tsipras said.

Greece and Turkey have long had tense relations and are divided over several issues, including territorial disputes in the Aegean. Athens often complains that Turkish fighter jets violate its airspace, sometimes flying directly over Greek islands, and Greek and Turkish warplanes often engage in mock dogfights.

"A short while ago I had the honour of being welcomed here on Agathonissi by some fighter jets from the Turkish airforce," Tsipras said during a speech on the island. "They wanted to also participate in our national celebration."

The prime minister was on the island to celebrate the anniversary of Greece's 1821 revolution against the Ottoman Empire, the precursor to modern-day Turkey.

"They must know that these silly actions make no sense. They waste kerosene and gasoline," Tsipras said of Turkey.

Tsipras stressed Greece is committed to dialogue and cooperation with Turkey, but that if necessary "we will do what our ancestors taught us, to defend our rights and our sovereignty."

The two neighbors and NATO allies have come to the brink of war three times since the mid-1970s, over the divided island of Cyprus and territorial issues in the Aegean, although they have also enjoyed periods of relatively good ties.

Turkish officials rejected the accusation.

A Turkish security official, speaking on condition of anonymity in line with government rules, said there was "no question of any harassment attempt by the Turkish planes during the Greek prime minister's activity today. The Turkish planes carried out their routine duties."

Greece's main opposition party criticized the Turkish fighter jets' actions.

"It is not the first time in recent years that Turkish provocation has been expressed even against the representatives of our country's political leadership," said Giorgos Koumoutsakos, who handles foreign affairs for the conservative New Democracy party. "Nor is it the first time Ankara provocatively ignores even the days on which Greeks celebrate their history and religion."

In Athens, Greeks marked independence day with a military parade complete with tanks and military aircraft flying by the ancient Acropolis. Student parades were also held.

Security was tight following concerns of protests by opponents of a deal Greece recently reached with neighboring North Macedonia, under which the country changed its name in return for Greece dropping its objections to the former Yugoslav republic joining NATO.

In the northern city of Thessaloniki, capital of the Greek province of Macedonia, one of the participants in the local parade held a placard reading: "Traitors, God forgives, the Greek Macedonians never." Protesters who tried to reach the area where officials were watching the parade were held back by police.

Police in one Athens neighborhood arrested 12 people after scuffles broke out, charging them with throwing Molotov cocktails, attacking police, causing injuries and other crimes.

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Costas Kantouris in Thessaloniki, Greece and Suzan Fraser in Istanbul contributed.