Moscow(CNN) A Moscow court sent Russian opposition leader Alexey Navalny to prison for more than two and a half years on Tuesday, prompting protests across the country. The ruling closed a heated hearing in which the Kremlin critic ridiculed claims he broke his parole conditions while recovering from poisoning, and denounced President Vladimir Putin as "Putin the poisoner."
Navalny was first detained two weeks ago upon his return to Moscow from Berlin, where he spent several months recovering from poisoning with nerve agent Novichok -- an attack he blames on Russian security services and on Putin himself,
The court on Tuesday ruled that while Navalny was in Germany, he violated probation terms from a 2014 case in which he had received a suspended sentence of three and a half years.
That suspended sentence will now be replaced with a prison term. The judge took into account the 11 months Navalny had already spent under house arrest as part of the decision.
He will appeal the verdict, according to his lawyer Olga Mikhailova. Speaking outside the courthouse after the sentencing, she said Navalny took the verdict "bravely as usual."
The verdict sparked swift condemnation abroad. US Secretary of State Tony Blinken called on the Russian government to "immediately and unconditionally release" Navalny. The UK, Germany, France and others issued similar statements.
It also inflamed anger among Navalny's supporters, who took to the streets in vast crowds on Tuesday night.
In central Moscow, protesters calling for his release were met with a show of force from authorities, as hundreds of riot police combed the vicinity of the courthouse street by street and forced individuals into waiting buses.
More than 1,000 people have been detained across Russia, according to independent monitoring organization OVD-Info.
Navalny's team later posted a message to Telegram thanking supporters and urging them to go home. "Putin failed to kill Alexey Navalny - and therefore decided to put him in jail for 2 years and 8 months. We will never tolerate a government that kills opponents and imprisons innocent people," it read.
"We will definitely take to the streets of the city again. For now just get carefully to the nearest metro station."
As he listened to the judge read out the lengthy verdict, Navalny drew a heart on the glass box he was confined in for his wife, Yulia Navalnya, who was in the court room.
Earlier, he had ridiculed allegations that he could have better informed parole officers of his whereabouts while comatose to the objections of prosecutors and repeatedly being told by the judge to stop speaking.
When prison service representative asked why he had not provided documents to explain the serious reasons that prevented him from showing up for inspections, Navalny shot back: "Coma?"
"Why are you sitting here and telling the court you didn't know where I was? I fell into a coma, then I was in the ICU, then in rehabilitation. I contacted my lawyer to send you a notice. You had the address, my contact details. What else could I have done to inform you?" he said.
Navalny's defense lawyers argued the prison service was well aware of Navalyny's whereabouts as it received a notice from him in early December. His lawyers also presented a letter from Berlin's Charite Clinic showing that he was in rehabilitation up until his return to Russia.
"The President of our country said live on air he let me go to get treatment in Germany and you didn't know that too?" Navalny also said. Putin has said that he personally "gave the order" to let Navalny be medically evacuated to Germany.
In a separate outburst, Navalny described Putin as a "little thieving man in his bunker" who "doesn't want me to set foot on the ground in Russia."
"The reason for this is the hatred and fear of one person who is hiding in the bunker. I've offended him so deeply by the fact that I've survived," Navalny charged.
When a prosecutor tried to object, Navalny snapped back: "I don't need your objections."
"He can pretend he is this big politician, the world leader, but now my main offense to him is that he will go down in history as Putin the Poisoner. There was Alexander the Liberator and Yaroslav the Wise, and there will be Vladimir the Poisoner of Underpants," Navalny added.
"He is not engaging in geopolitics, he holds meetings on how to smear underwear with chemical weapons."
Kremlin spokesman Dmitry Peskov said earlier that Putin was not planning on following Navalny's hearing Tuesday, and was instead meeting with "teachers who are teaching the future generation of Russia."
Navalny fell ill from exposure to military-grade Novichok during a trip to Siberia in August. He blames the attack on Russian security services and on President Vladimir Putin himself, accusations that the Kremlin has repeatedly denied.
A CNN-Bellingcat investigation in December implicated the Russian Security Service (FSB) in Navalny's poisoning, piecing together how an elite unit at the agency trailed the activist and his team for years, including on the trip to Siberia.
Navalny also duped one of the agents into revealing that he was poisoned with the nerve agent Novichok applied to his underwear.
Putin pushed back in December saying that if Russian security services had wanted to kill Navalny, they "would have finished" the job, though he did not dispute any details of the findings.
A perennial thorn in Putin's side, Navalny has been arrested and detained several times but had until now avoided lengthy sentences.
The case in which Navalny was sentenced on Tuesday dates back to 2014, when he and his brother Oleg were convicted of embezzling about $500,000 from two Russian firms between 2008 and 2012. Both were sentenced to three-and-a half years in prison, but Alexey's sentence was suspended.
Navalny has insisted that the case is politically motivated. Under Russian law, convicted criminals are barred from running for political office.
In 2017, the European Court of Human Rights ruled that the brothers were unfairly convicted in the case and that Russian courts handed down "arbitrary and manifestly unreasonable" decisions in the case.
In the weeks leading up to Tuesday's hearing, fears of political repression have grown as many of Navalny's key allies and some family members were detained or put under house arrest.
Yulia Navalnaya has been arrested twice since she returned to Moscow with her husband.
"Yulia, they show you on TV and keep talking about your radical behavior. Such a bad girl, I'm proud of you," Navalny said shortly before his hearing began.
On Tuesday, CNN reporters witnessed police detaining dozens of people outside the court before the hearing began.
As the day went on, cars honked in solidarity and marching protesters booed police cars as they drove by. Van after van full of detainees could eventually be seen driving past the cordoned-off Kremlin.
Navalny's allies have called for another round of nationwide demonstrations this weekend.