Russia was preparing to use nuclear weapons

Vladimir Putin has said Russia was so fearful of attack at the height of the Ukraine crisis that it was preparing to arm its nuclear weapons, in extraordinary claims aired on state TV on Sunday night.

Amid ongoing Russian media speculation that the President was watching the Crimea documentary from his sickbed, Putin's full interview with Rossiya One provided new insight into his country's involvement in the annexation of the Black Sea peninsula.

In the documentary, which marks a year since the referendum that saw Russia take control of Crimea, Putin described the Ukrainian revolution to oust Viktor Yanukovych in February 2014 as an armed coup "masterminded by our American friends".

He said Washington tried to "trick" the world into thinking the regime change was "supported mostly by the Europeans", according to a translation of the interview on Russia Today.

But he instead accused the US of orchestrating the crisis, saying: "They helped training the nationalists, their armed groups, in Western Ukraine, in Poland and to some extent in Lithuania. They facilitated the armed coup."

And on Russia's willingness to arm nuclear weapons if necessary, Putin said: "We were ready to do this ... (Crimea) is our historical territory. Russian people live there. They were in danger. We cannot abandon them."

A woman holds a USSR naval flag during a rally marking the one-year anniversary of Crimea voting to leave Ukraine and join the Russian state in central Sevastopol yesterday. Photo: AFP

Meanwhile, the EU warned yesterday of a continued Russian military build-up in Crimea as it condemned Moscow's "illegal annexation" of the peninsula from Ukraine one year ago.

Diplomatic chief Federica Mogherini said the 28-nation bloc was also deeply concerned at the deterioration of human rights, demanding free access for outside monitors to investigate the situation.

"The EU reaffirms its deep concern at the continuous military build-up and deterioration of the human rights situation in the Crimean peninsula, including the denial of free speech and the persecution of persons belonging to minorities," said a statement by Mogherini approved by the EU's foreign ministers.

The European Union, which has hit Russia with tough economic sanctions over its intervention in Ukraine, "does not recognise and continues to condemn this act of violation of international law," the statement said.

"The illegal annexation of Crimea and Sevastopol ... is also a direct challenge to international security, with grave implications for the international legal order that protects the unity and sovereignty of all states," it added.