ANKARA — Despite recent optimistic statements from Turkish and US officials about Turkey’s potential return to the F-35 fighter jet program, US Ambassador to Turkey Tom Barrack emphasized Tuesday that Ankara must end its possession of the Russian S-400 system for the move to happen. His remarks signal a stall in negotiations and leave Turkey with limited options.

“As laid out in US law, Turkiye must no longer operate nor possess the S-400 system to return to the F-35 program,” Barrack wrote on X late Tuesday.

He added that the positive ties between President Donald Trump and his Turkish counterpart, Recep Tayyip Erdogan, led to “the most productive talks on this issue in nearly a decade,” in reference to ongoing technical talks over the issue, expressing hope for “a breakthrough in the coming months.”

His late-night tweet came after Turkish Foreign Minister Hakan Fidan also told Reuters last week that the issue would be resolved “very soon." However, observers say the two capitals still must find a compromise on the issue. Turkey has maintained the system within its territory, even if non-operational, while Washington insists Ankara formally end its possession.