Russia’s full-scale invasion of Ukraine in February 2022 heightened Turkey’s importance as a Nato bulwark in the Black Sea region.

“My approval of Turkey’s request to purchase F-16 aircrafts has been contingent on Turkish approval of Sweden’s Nato membership,” said Democratic Senator Ben Cardin, chair of the Senate Foreign Relations Committee, one of four key committees that needs to approve arms transfers.

“But make no mistake: This was not a decision I came to lightly.”

He said Turkey’s human rights record needed to improve, as well as doing more to hold Russia accountable for its full-scale invasion of Ukraine.

Now Hungary is the sole Nato member yet to ratify Sweden’s accession, although there have been recent signs of progress.

Last year, the US approved the transfer to Ukraine of American-made F-16 fighter jets from Denmark and the Netherlands, once Ukrainian pilots are fully trained to operate them.