US President Donald Trump said Wednesday that he remains undecided on a potential sale of F-35 fighter jets to Turkey, following the NATO Summit in Ankara.

Speaking during a media briefing after the summit, Trump said Turkish President Recep Tayyip Erdogan “has helped us in so many different ways,” before clarifying that no decision had been made regarding the F-35s.

In the lead-up to the NATO meeting, Trump had suggested that he could lift sanctions imposed on Turkey to facilitate the sale of the aircraft.

Turkey’s interest in acquiring F-35s faces legal obstacles as a result of Ankara’s purchase of the Russian-made S-400 missile system.

The issue was pointed out by Greek Prime Minister Kyriakos Mitsotakis in comments to media after the summit. Mitsotakis also said Greek pilots are expected to begin training on Greece’s first F-35 fighter jets in 2027.