"It is our intention to acquire a squadron of F-35s, with a possible option on a second (squadron)," Prime Minister Kyriakos Mitsotakis said at the end of a two-day NATO summit in Madrid.

Mitsotakis said Greece had sent a letter of request for possible delivery of the planes in 2027 or 2028.

Greece's conservative government has been steadily modernising the country's armed forces in the face of threats from neighbouring Turkey.

It has already signed a multi-billion-euro deal with France for Rafale jets and Belharra frigates.

The move was criticised by the main opposition Syriza party for being too costly.

"We are a small country with weak finances," senior Syriza official Nikos Filis told Athens 98.4 radio Thursday.

"The government had said we would purchase Rafales instead of F-35s. Now we are getting both. This story has no end," Filis said.

Mitsotakis said earlier this year there was an "urgent need" to upgrade the Greek air force, which regularly engages in mock dogfights with Turkish jets in Aegean airspace disputed by Ankara.

The conservative Greek PM in 2020 unveiled the country's most ambitious arms purchase programme in decades after a dangerous stand-off with Turkey over hydrocarbon resources and naval influence in the waters off their coasts.

Turkish authorities now accuse Greece of stationing troops on Aegean islands in violation of the peace treaties that followed World War I and World War II.

Athens counters that the troops are stationed in response to the presence of Turkish military units, aircraft and landing craft on the opposite coast.