ANKARA: President Tayyip Erdogan said Turkey's talks with the United States on the modernisation of F-16 fighter jets was going well, Turkish broadcaster HaberTurk and other media reported on Wednesday.

Ties between Ankara and Washington have been strained in recent years over issues including Turkey's purchase of Russian S-400 missile systems, which triggered US sanctions.

Erdogan was quoted as telling reporters on a flight returning from a trip to Africa that the crisis between Ukraine and Russia had shown the necessity of the S-400s purchase, given the security risks in the region.

Ankara had previously ordered more than 100 US F-35 jets, but Washington removed Turkey from the programme after it bought the S-400s. Turkey has called the move unjust and demanded reimbursement for its $1.4 billion payment.

Erdogan has said that payment should be used to finance some of Turkey's request to buy 40 F-16s and nearly 80 modernisation kits. President Joe Biden has said the F-16 request had to go through a process in the United States.