Ukraine’s President Volodymyr Zelenskiy said on Tuesday he received “a serious, powerful” offer from leaders of countries ready to provide Kyiv with F-16 fighter jets and is awaiting final agreements with key allies.

“Our partners know how many aircraft we need,” Zelenskiy was quoted as saying in a statement on his website. “I have already received an understanding of the number from some of our European partners … It is a serious, powerful offer.”

Kyiv now awaits a final agreement with its allies, including “a joint agreement with the United States,” Zelenskiy said. It is still unclear which Kyiv’s allies are ready to send the jets to Ukraine.

US President Joe Biden told G7 leaders last month that Washington supported joint allied training programmes for Ukrainian pilots on F-16s.

But US National Security adviser Jake Sullivan has said there was no final decision on Washington sending aircraft.

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Zelenskiy has long appealed for the F-16 jets, saying their appearance with Ukrainian pilots would be a sure signal from the world that Russia’s invasion would end in defeat.

Russia said on Tuesday that US-built F-16 fighter jets can “accommodate” nuclear weapons and warned that supplying Kyiv with them will escalate the conflict further.