The Russian leader described the weapons as a deterrent but reiterated that his country would use "all the means at our disposal" to defend its interests if "peaceful means" were to fail.

It is the latest in a number of statements since the start of the war in which he has kept open the nuclear option.

"We haven't gone mad. We fully understand what nuclear weapons are," Putin said in televised remarks to a member of the presidential Human Rights Council.

"We have them, and they are more advanced and state-of-the-art than what any other nuclear power has," he said. "We aren't going to run around the world brandishing those weapons, but we will naturally proceed from their existence."

"It's a factor of deterrence, not a factor provoking an escalation of the conflict."

Nonetheless, the president refused to rule out a hypothetical first strike, claiming that it would prevent Russia from defending itself.

He said Russia had a "launch on warning" doctrine, whereby Russia would fire nuclear weapons if targeted by an imminent nuclear attack - or by a conventional attack that threatened its existence.

"If it doesn't use it first under any circumstances, it means that it won't be the second to use it either, because the possibility of using it in case of a nuclear strike on our territory will be sharply limited," the president said.

Many Western countries have previously criticised Putin's nuclear comments as dangerous.

However, he claimed on Wednesday that he had been provoked by former UK prime minister Liz Truss when she spoke about Britain's own readiness to use nuclear weapons.

He appeared to be referring to comments made by Truss in August, in which she told a Tory hustings event she would be "ready" to use  WMDs (weapons of mass destruction) if necessary.

"I had to emphasise certain things in response," said Putin.

"Her comments went largely unnoticed, but they immediately emphasised our statements and used them to scare the world."

Sky News