File photo. [Kevin Lamarque/Reuters]

US President Donald Trump is expected to throw his support behind the potential sale of F-35 fighter jets to Turkey during a visit to Ankara, two sources familiar with the matter said on Tuesday, even as legal and congressional hurdles have yet to be fully resolved.

The move would be the biggest gesture yet from Trump – who is traveling to Ankara to attend a NATO summit – to Turkish President Tayyip Erdogan, whom he regularly praises and sees as a close ally. The two countries have enjoyed warmer ties since Trump returned to office last year.

Despite the warm relationship, Turkey’s 2019 acquisition of the Russian S-400 air defense system has ⁠remained a sore spot in bilateral ties. In response to ⁠Turkey’s purchase, Washington in 2020 imposed sanctions on a major Turkish defense company and removed Turkey from the F-35 stealth fighter jet program, where Ankara was also a production partner.

Congress also passed a law prohibiting any F-35 sales to Turkey as long as Ankara retained the S-400s, saying the Russian ​system posed a security risk to US-made combat aircraft. ⁠Currently, the US law does not permit Turkey to operate or possess the S-400 system if it wishes to rejoin the F-35 program.