President Biden sent a letter to four senior members of Congress on Wednesday urging them to quickly approve a $20 billion sale of F-16 fighter jets to Turkey, following the vote one day earlier by Turkey’s Parliament to allow Sweden to join the North Atlantic Treaty Organization, according to three U.S. officials.

The White House sent the letter to the top Democratic and Republican lawmakers on the Senate Foreign Relations Committee and the House Foreign Affairs Committee, which have oversight of arms transfers by the State Department to other nations. As of Wednesday night, the four senior lawmakers had not given their approval, and one or more of them might ask the Biden administration to give assurances about Turkey’s actions on some foreign policy issues before agreeing to the transfer, a congressional official said.

President Recep Tayyip Erdogan of Turkey, a member of NATO, has linked his country’s approval of Sweden’s accession to the security organization to the F-16 sales, which had been pending. Both Sweden and Finland had asked to join NATO after Russia’s full-scale invasion of Ukraine in February 2022, and the vast majority of the alliance’s members soon agreed. Turkey approved Finland’s bid but, along with Hungary, has withheld approval for Sweden.

Secretary of State Antony J. Blinken met with Mr. Erdogan in Istanbul this month and pushed him to have Turkey approve Sweden’s accession. Mr. Blinken tried to assure him that the F-16 sale would happen, U.S. officials said.

The State Department gave the two congressional committees informal notification of the sale more than one year ago, starting the review process by lawmakers. However, congressional officials have gone back to the department repeatedly with questions about how Turkey might use the jets, as well as some of Turkey’s foreign policy moves that seem to run counter to U.S. interests.