US President Joe Biden called his Turkish counterpart Recep Tayyip Erdogan on Monday to congratulate him on his re-election.

During the phone call, Erdogan raised the issue of acquiring American F-16 fighter jets, while Biden, for his part, asked Ankara to remove the obstacles it poses to Sweden’s accession to NATO.

“I spoke with Erdogan, I congratulated him. He still wants a solution for the F-16s. I told him we want a solution for Sweden…,” the US president told reporters before leaving the White House for Delaware. “We will say more next week,” he added.

Turkey sought to buy $20 billion worth of F-16 fighter jets from the US, but the US Congress blocked the sale.

Among the White House’s top priorities is Sweden’s NATO membership by the time of the NATO summit in Lithuania in mid-July. Turkey approved Finland’s accession to NATO in late March, but continues to block Sweden’s entry.