Russia says ready to use nuclear weapons in Ukraine conflict

When asked if he would have put his nuclear arsenal on alert, he responded: “We were ready to do that … That’s why I think no one wanted to start a world conflict”.

He said he also deployed high-tech coastal defence missiles, which can be seen from space, to deter outside intervention.

He added that he warned his Western counterparts he is prepared to go to war: “I spoke to colleagues and I told them that this is our historic territory, Russian people live there, they are in danger and we can’t abandon them. What do you want to fight for? You don’t know? We know. And we’re ready for that”.

The film also revealed that he sent Russian special forces to the Ukrainian peninsula prior to its so-called referendum on independence, which took place on 16 March last year.

His remarks are not the first instance of nuclear sabre-rattling in the crisis.

Russian strategic bombers, sometimes with nuclear payloads, have flown sorties on the edge of Nato airspace in recent months.

Russian propaganda outlets have said it is capable of reducing the US to "radioactive ash".

Putin has also claimed he could conquer Kiev, Bucharest, and Warsaw “in two days” by conventional means if he is provoked.

Military analysts, such as Pavel Podvig, of the UN’s Institute for Disarmament Research in Geneva, and Igor Sutyagin, from the Rusi think tank in London, previously told EUobserver the nuclear bluff is not credible.

They noted the most likely scenario is that Putin could fire a small-scale, or “tactical”, nuclear weapon against a remote island to cause fear if he felt threatened by Nato.

The Putin documentary, filmed over eight months, was aired amid speculation on his whereabouts.

He hasn't been seen in public for over 10 days, prompting rumours of illness or of a Kremlin coup, but he is due to meet the president of Kyrgyzstan in St Petersburg on Monday.

The Crimea nuclear threat was also aired amid concern Russia will shortly attack the Ukrainian city of Mariupol.

The European Commission and the EU foreign service, an EU source said, have finalised a package of new economic sanctions which could be imposed if he does.

But speaking to European media at the weekend, EU Council chief Donald Tusk noted how hard it is to maintain EU unity.

“A common policy of the 28 member states doesn’t exist. We have 28 different foreign policies”, he said.

He noted he has little faith in the recent, so-called Minsk 2, ceasefire accord. But he said it gave Kiev the chance to “prepare for a long, long conflict”. He added that any EU leader who believes Putin is ready to make peace is guilty of “naivete or hypocrisy”.

“The only effective answer to Putin’s clear and simple policy is pressure”, he said.