ANKARA, Turkey (AP) -- Turkey and Britain on Wednesday signed a preliminary agreement for the sale of Eurofighter Typhoon fighter jets to Turkey, a significant step in Ankara's efforts to modernize its air fleet.

Turkish Defense Minister Yasar Guler and his British counterpart, John Healey, inked a memorandum of understanding during a defense industry fair in Istanbul, Turkey's Ministry of National Defense said.

NATO member Turkey has long aimed to buy 40 Eurofighter jets, which are built by a consortium of British, German and Italian companies. Germany reportedly initially opposed the sale but later reversed its position. Britain led negotiations on behalf of the consortium.

A Turkish defense ministry statement said the memorandum takes the two countries "one step closer to a full agreement on the Typhoon."

"Both Ministers welcome signature as a positive step towards bringing Turkey into the Typhoon club and share a mutual ambition to conclude the necessary arrangements as soon as possible," it added.

Turkish officials have said that they are still negotiating over pricing and technical terms, saying that they have received an initial offer and expect to submit a counter-proposal.

Turkey is also seeking to return to the U.S.-led F-35 fighter jet program, from which the country was ousted in 2019, following its purchase of Russian-made S-400 missile defense systems. The U.S. said the systems posed a risk to the F-35s.

Turkey is also developing a domestic fifth-generation fighter jet, the KAAN, which is slated to be operational in 2028.