The S-400 acquisition has been a defining constraint on U.S.–Türkiye defense ties since 2019, when Washington removed Ankara from the F-35 program. Bloomberg said recent contacts suggest Turkish leaders are testing whether the decision can be reversed without rupturing ties with Moscow.

Bloomberg News reported that President Recep Tayyip Erdogan raised the prospect of returning the S-400 system during talks with Russian President Vladimir Putin in Turkmenistan last week, following earlier discussions between officials.

Türkiye purchased the S-400s nearly a decade ago, a move that culminated in its expulsion from the F-35 program in 2019. In 2020, Washington imposed sanctions under the Countering America’s Adversaries Through Sanctions Act (CAATSA), restricting the Turkish defense industry’s access to sensitive U.S. technology. NATO has argued that integrating the Russian system with Western aircraft could compromise allied intelligence; Ankara does not operate the system.

A Possible Timeline

According to Bloomberg, pressure from Washington has intensified as Ankara seeks a reset. The S-400 issue was discussed during Erdogan’s White House meeting with President Donald Trump in September. U.S. Ambassador to Türkiye Tom Barrack said earlier this month that Ankara was edging closer to giving up the system, predicting the matter could be resolved within “four to six months.”

Turkish officials have linked progress to sanctions relief and renewed access to F-35 stealth fighters. A senior Turkish diplomat recently said he expected U.S. sanctions to be lifted next year. Reentry into the F-35 ecosystem would restore Türkiye’s role in a program it helped build before 2019 and address capability gaps created by its removal.

Possibility of a Refund

Bloomberg reported that Ankara is also seeking a refund for the S-400 purchase, which cost billions of dollars. One option under discussion is offsetting the amount against Türkiye’s oil and natural gas import bill from Russia, though officials cautioned that such terms would require negotiation.