(Updates with information that Biden-Erdogan meeting finished)
By Humeyra Pamuk and Andrea Shalal
MADRID, June 29 (Reuters) - The Biden administration threw its support on Wednesday behind the potential sale of U.S. F-16 fighter jets to Turkey, a day after Ankara lifted a veto of NATO membership for Finland and Sweden.
Celeste Wallander, Assistant Secretary for Defense for International Security Affairs at Pentagon, told reporters on a call that strong Turkish defense capabilities would reinforce NATO's defenses.
"The United States supports Turkey’s modernization of its fighter fleet because that is a contribution to NATO security and therefore American security," she said.
"These plans are in the works. And, they need to be worked through our contracting processes," she added.
Turkey made a request in October to the United States to buy 40 Lockheed Martin-made F-16 fighters and nearly 80 modernization kits for its existing warplanes.
Washington had not previously openly expressed any opinion on the sale aside from saying all weapons sales would have to go through the necessary legal process.
In March, the State Department wrote a letter to some members of the U.S. Congress who had opposed the sale, saying "appropriate" U.S. defense trade ties with Turkey would serve U.S. interests.
Wallander's comments come on the heels of an 11th hour deal struck on Tuesday between Turkey, Finland and Sweden after four hours of talks, averting an embarrassing impasse at the gathering of 30 NATO leaders that aims to show resolve in the face of Russia's invasion of Ukraine.
U.S. President Joe Biden, speaking before his meeting with Turkish President Tayyip Erdogan on the sidelines of the NATO summit in Madrid praised Erdogan's efforts to help strike a deal with the Nordic countries. "I want to particularly thank you for what you did," Biden said.
The three nations signed a deal under which Ankara lifted its block on Finnish and Swedish membership, while the candidates pledged not to support the Kurdish militant PKK and YPG groups, or the network of U.S.-based cleric Fethullah Gulen, which Turkey blames for a failed 2016 coup attempt.
U.S. officials pushed back against any suggestion that Washington was backing the warplane request to remove Turkish objections to the entry of Sweden and Finland into NATO.
"The U.S. did not offer anything to Turkey and was not asked for anything by Turkey” as part of its agreement with Finland and Sweden, a senior administration official said.
The official said U.S. officials were engaged in ongoing technical talks about Turkey’s request to buy U.S. F-16 fighter jets. Congress would have the final say about any such sales.
Erdogan, before departing for Madrid on Tuesday but after a phone call with Biden, criticised the United States over the F-16 sale, saying it was stalling Ankara.
In his brief remarks before his meeting with Biden, Erdogan did not bring up the F-16 issue but expressed his pleasure to meet Biden "after a long while." Their meeting lasted about an hour.
The two leaders had last met in person in October 2021 and spoke on the phone earlier this year.
The sale of U.S. weapons to NATO ally Turkey became contentious after Ankara acquired Russian-made defense missile systems, triggering U.S. sanctions as well as Turkey's removal from the F-35 fighter jet program. (Reporting by Humeyra Pamuk Editing by Peter Graff and Alistair Bell)