President Vladimir Putin has warned the West not to cross Russia’s “red lines”, saying Moscow would respond swiftly and harshly to any provocations and those responsible would regret it.

In his annual state of the nation address, the Kremlin leader sent a message of Russian strength and defiance in the face of outside threats.

“In some countries, they have developed a highly unseemly habit of picking on Russia for any reason, and most often for no reason at all – a kind of sport,” Mr Putin said, standing alone on a vast stage flanked by white, blue and red national flags.

“Organisers of any provocations that threaten our core security interests will regret what they have done like they’ve never regretted anything for a long time.”

He said Russia’s response will be “asymmetrical, swift and harsh”.

“We want good relations … and really don’t want to burn bridges,” Mr Putin said.

“But if someone mistakes our good intentions for indifference or weakness and intends to burn down or even blow up these bridges, they should know that Russia’s response will be asymmetrical, swift and harsh.”

Russia would determine where its red line lay in each specific case, he said, comparing those who attack it to hyenas led by a tiger.

Relief over Ukraine

With about 100,000 Russian troops currently massed on Ukraine’s border and Ukraine’s president warning openly of the possibility of war, some analysts had speculated that Mr Putin might use his annual address to announce he would be sending troops into Ukraine.

So, despite the tough rhetoric, the rouble firmed after the speech, with markets interpreting it as not escalating tensions with the West.

The rest of Mr Putin’s a speech focused on Russia’s response to the COVID-19 pandemic and resulting economic hardship. He announced new social support measures for families with children ahead of a September parliamentary election.

Thousands protest in support of Navalny

In his speech, Mr Putin made no mention of opposition politician Alexei Navalny, who is on hunger strike in prison and reported to be close to death.

But even as Mr Putin was speaking, protesters were rallying in support of Mr Navalny, who survived a nerve agent attack last year.

Protests were held across Russia in support of imprisoned Kremlin critic Alexei Navalny. Photo: Getty

Russian police rounded up more than a thousand protesters in dozens of cities, as Mr Navalny’s spokeswoman was jailed for 10 days, and another close ally detained.

OVD-Info, a group that monitors protests and detentions, said 1004 people had been arrested, including 351 in St Petersburg and 87 in the Urals city of Ufa.

The opposition had hoped the rallies would be the biggest in modern Russian history, and presented them as an attempt to save Mr Navalny’s life by persuading the authorities to allow his own doctors to treat him.

But turnout looked smaller than during protests earlier this year before Mr Navalny was jailed for two-and-a-half years for parole violations related to what he said were trumped up charges of embezzlement.

-AAP