The Ukrainian leader made the comments at an EU summit on Thursday, in which he said "either Ukraine will have nuclear weapons, which will protect us, or we must have some kind of alliance".

"This is a dangerous provocation," Putin said at a meeting with journalists from the BRICS group of emerging economies, warning: "Any step in this direction will be met with a corresponding reaction."

"It is not difficult to create nuclear weapons in the modern world," Putin added.

"I do not know whether Ukraine is capable of doing it now, it is not so easy for Ukraine of today, but in general there is no great difficulty here."

Zelensky sought to clarify his words in a televised interview Friday, saying he wanted "to be understood very correctly".

Ukraine "did not intend to create any threat to the world nor any nuclear weapons", he told a group of journalists.

His original comments Thursday referred to a conversation he had with former US president Donald Trump about Ukraine giving up its nuclear arsenal after the collapse of the Soviet Union.

Ukraine inherited the world's third-largest nuclear arsenal when the Soviet Union broke up in 1991. It surrendered it three years later after receiving security guarantees from Russia and the United States.

Those security guarantees, known as the Budapest Memorandum, required that the signatories respect Ukraine and the other ex-Soviet republics' territorial integrity and independence.

Under the Budapest Memorandum, Ukraine "gave up nuclear weapons and was guaranteed security (and) territorial integrity" but "received nothing for it", Zelensky said Friday.

Ukraine is not seeking to regain its nuclear umbrella but wants NATO membership, he said.

"We are a peaceful state. NATO is better today than any kind of weapon. Especially such a threatening one."