Russia was ready to bring its nuclear weapons into a state of alert during last year's tensions over the Crimean Peninsula, President Vladimir Putin says.
Putin has also expanded on a previous admission that the well-armed forces in unmarked uniforms who took control of Ukrainian military facilities in Crimea were Russian soldiers.
His comments, in a documentary being shown on state TV, highlight the extent to which alarm spread in Russia in the weeks following Ukrainian President Viktor Yanukovych's ouster in February 2014 after months of street protests.
The documentary comes as speculation swirls about Putin's 10-day absence from public view.
On Monday, he will meet with the president of Kyrgyzstan in an event covered by the news media, which would be his first appearance before journalists since March 5.
After Yanukovych fled Kiev, eventually surfacing in Russia, separatist sentiment soared in Crimea, the Black Sea peninsula dominated by ethnic Russians.
Russian forces took control of Ukrainian military facilities on the peninsula and a referendum on secession was hastily called.
The referendum, which was widely denounced in the West as illegitimate, reportedly brought overwhelming support for secession. Russia annexed Crimea on March 19, 2014.
In the documentary, which marks a year since the referendum, Putin says of the nuclear preparedness: "We were ready to do this ... (Crimea) is our historical territory. Russian people live there. They were in danger. We cannot abandon them."
The comments were reported on the state broadcaster's website after its transmission in the Russian Far East and before it appeared on the air in Moscow.
Putin said his plans for a Crimean operation started after Yanukovych fled.
"We never thought about severing Crimea from Ukraine until the moment that these events began, the government overthrow," he said, repeating Russia's contention that Yanukovych was the victim of a coup.
