French Foreign Minister Jean-Yves Le Drian has condemned as "unbearable" the Russian determination to break hunger-striking opposition figure, Alexei Navalny, warning that the European Union will not hesitate to sanction Vladimir Putin and the Russian authorities in the event of Navalny's death in prison.
Thousands of people took to the streets across Russia on Wednesday evening, demanding freedom and proper medical attention for Navalny, who has been hunger strike for three weeks in a detention centre outside Moscow.
The opposition staged demonstrations in dozens of Russian cities, with the largest rallies taking place in Moscow and Saint Petersburg.
The OVD-Info monitoring group, which tracks detentions at opposition protests, said that by Thursday morning police had detained "more than 1,783 people in 97 cities", 805 of them in Saint Petersburg.
He was sentenced to two-and-a-half years on allegations of fraud and has been serving time in a penal colony about 100 kilometres east of Moscow. He claims the verdict and his subsequent imprisonment were politically motivated.
Navalny's health has been failing since he launched his hunger strike to demand proper medical care for a range of ailments, including back pain and numbness in his limbs.
A group of UN rights experts expressed alarm Wednesday over his deteriorating health.
"We believe Mr Navalny's life is in serious danger," they warned, calling on Russian authorities to allow Navalny "to be evacuated for urgent medical treatment abroad".
Stark warning from French Minister Le Drian
French Foreign Minister Jean-Yves Le Drian has warned that Navalny's life is clearly in danger, saying that, if he dies in custody, "we will impose the necessary sanctions . . . putting the responsibility for this tragedy firmly at the door of Mr Putin and the Russian authorities".
Le Drian has criticised three dangerous tendencies evident in current Russian policy.
The first is "an internal drift towards authoritarianism," clear in the treatment of Navalny.
The second, according to the French foreign affairs chief, is "an external drift towards provocation and intimidation," notably at the border with Ukraine, where more than 100,000 Russian soldiers have recently been deployed.
And the third dangerous tendency of the Kremlin, according to Le Drian, is "a drift towards interference in the internal affairs of sovereign states, threatening the working of our democratic model".
Putin tells the West not to cross Russian red line
Meanwhile, President Vladimir Putin warned the West on Wednesday against "crossing the red line" with Russia.
Putin said Moscow would respond swiftly and harshly to moves against its interests.
"The organisers of any provocations threatening the fundamental interests of our security will regret their deeds, more than they have regretted anything in a long time," Putin said.
Putin unsurprisingly made no mention of Navalny in his state-of-the-nation speech, delivered on Wednesday -- he has always refused to use the name of his most prominent opponent.
The Russian leader did however hit out at rivals abroad, with Moscow and Western capitals at loggerheads over a Russian troop build-up on Ukraine's borders and a series of espionage scandals that have resulted in diplomatic expulsions.
"I hope that no one will think of crossing the red line in relation to Russia. And where it will be -- we will determine that ourselves," Putin said.