A Russian court has ordered opposition leader and anticorruption activist Aleksei Navalny to be jailed for 15 days for disobeying police, one day after he was arrested near the site of a demonstration in central Moscow.
The March 27 ruling comes after an earlier decision by the court to fine Navalny 20,000 rubles ($350) for organizing what the authorities say was an illegal protest in the Russian capital on March 26.
Navalny was detained on that date as he made his way to an anticorruption demonstration that he had called on people to attend in Moscow.
The government says the protest was illegal because city authorities had not granted permission for a march and rally in the center of the city, and that it led to violations of public order. Navalny disputes that, saying that it was legal.
Police also detained hundreds of other demonstrators at anticorruption protests that were attended by thousands of people in dozens of cities nationwide in the largest such rallies since 2012.
A day after the anticorruption protests, the Kremlin lashed out.
Russian President Vladimir Putin's spokesman, Dmitry Peskov, said on March 27 that many of the protests the previous day were illegal and that organizers had "provoked" participants into "illegal activity."
Peskov also claimed that children had been promised "rewards" for taking part. The same day, Russia's Investigative Committee opened a probe into possible payments to demonstrators -- "not only youths, but to other participants as well."
Peskov pointed out that the authorities in Moscow declined to give Navalny permission to hold a march and rally at a central location and proposed alternate sites on the outskirts of the city.
Navalny contends that there were no grounds for the government to refuse permission, and that the alternate sites were offered later than is required by law.
A total of tens of thousands of people took part in the demonstrations on March 26, and a group called OVD-Info says more than 1,000 were detained in Moscow alone.
OVD-Info said on March 27 that most of those detained had been released but that at least 120 remained in custody.
Moscow police said 500 people had been detained.
The United States and the European Union have condemned the mass arrests of protesters in Russia and called for their prompt release.
The U.S. State Department said Washington was "troubled" by Navalny's detention.
"We call on the government of Russia to immediately release all peaceful protesters," State Department spokesman Mark Toner said in a statement issued on March 26.
"Detaining peaceful protesters, human rights observers, and journalists is an affront to core democratic values," Toner said.
The EU also called on Russia to allow people "basic freedoms of expression, association, and peaceful assembly."
Speaking in Moscow on March 27, Russian Foreign Minister Sergei Lavrov accused the West of applying a "double standard" regarding protests in Russia.
He said international law recognizes "freedom of speech and the right for gatherings, as well as exceptions when it concerns state security and the moral well-being of society."
The nongovernmental organization Amnesty International issued a statement saying that Navalny "and all the peaceful protesters detained after the mass demonstrations…must be immediately released."
The statement said the detentions demonstrate the Russian government's "profound disdain for the right to freedom of expression and assembly."
The rallies followed a report released by Navalny's Anticorruption Foundation (FBK) accusing Prime Minister Dmitry Medvedev of using charities and NGOs to collect donations from tycoons and state banks and using the funds to buy expensive assets.
According to accounts from the court hearing on March 27, Navalny at one point called for Medvedev to testify.
He also critized the judge, Alesya Orekhova, accusing her of behaving like a rude teenager.
"Your honor, I have a 15-year-old daughter. When she is wrong, she starts taking back -- like you are doing," a person with the Twitter handle Vladlen Los quoted Navalny as saying.
Navalny was detained as he emerged with supporters from a subway station on March 26 in central Moscow.
Navalny helped lead a series of major protests in 2011-12 that were sparked by anger over evidence of widespread fraud in parliamentary elections and dismay at Vladimir Putin's return to the presidency after a stint as prime minister.
Posting on Twitter from his cell after he was detained, Navalny wrote he was "proud" of the protesters and said the arrests were "understandable."
"The thieves defend themselves this way. But you cannot arrest everyone who is against corruption. There are millions of us," he wrote.
In a tweet on March 27, Navalny said that 13 employees of his foundation remained in police custody after they were detained when the group's office in Moscow was searched on March 26 by law-enforcement authorities.
"The office was robbed: They took away absolutely all the equipment," Navalny wrote.
Russia's Interfax news agency said 130 people were arrested in St. Petersburg.
The size of the March 26 protests was remarkable because they were unauthorized. Recent laws have tightened criminal punishment for protests that are not permitted by city authorities.
Navalny announced in December that he would run for president next March, when Putin is widely expected to seek a new six-year term.
Russian authorities have said Navalny will be barred from the ballot if a conviction on charges of financial crimes is upheld on appeal. But he has pushed ahead with his campaign.
Navalny has said the two previous convictions in two separate cases were politically motivated punishment for his opposition to Putin.
With reporting by Mediazona and rapsinews.ru