Turkish President Tayyip Erdogan said problems over the F-35 jet programme will be the main topic at his meeting with U.S. President Joe Biden at a summit in Glasgow starting at the end of this month, state media reported on Wednesday.

Turkey, a manufacturer and buyer of the F-35s, was expelled from the programme over its purchase of Russian S-400 defence systems. It says its removal is unjust and has demanded reimbursement of $1.4 billion.

Erdogan has said Washington offered Ankara a package of F-16 jets and modernisation kits in exchange for the payment, but the United States has said it offered no such financial plan.

"The information we received is that there is a payment plan of some sort with them," state-run Anadolu news agency cited him as telling reporters regarding the F-16s.

"Whether this is true or not, we will find out from them. It will be good for me to discuss this with Mr. Biden at the highest level. If so, we will go for a deal in that regard," he said on a flight returning from a visit to Azerbaijan.

Glasgow will host the U.N. COP26 climate summit between Oct. 31-Nov. 12. Erdogan said previously he would meet Biden at the G20 summit in Rome at the end of this month.

Turkey and its Western allies climbed down from a full-blown diplomatic crisis on Monday after foreign embassies said they abide by diplomatic conventions on non-interference, averting a threatened expulsion of 10 ambassadors. 

Asked about U.S. media headlines that Erdogan had taken a step back in the row, Erdogan said: "How did I take a step back? I'm on the offensive. There is no stepping back in my book."

The ambassadors, including the U.S. envoy, had called on authorities last week to free Osman Kavala, a philanthropist detained for four years on charges of financing protests and involvement in an attempted coup. He denies the charges.

The Council of Europe has said it was set to begin infringement proceedings against member state Turkey at its end-November meeting if Kavala is not released in line with a European Court of Human Rights (ECHR) ruling. 

Asked about that meeting, Erdogan said: "We will listen and see what they say. We will listen to the ECHR and the Council. After listening we will do what is necessary."