MOSCOW — Russia on Friday expelled three European diplomats whom it accused of participating in illegal protests in support of the jailed opposition leader Aleksei A. Navalny — a move announced as the European Union’s foreign policy chief was visiting Moscow and as Mr. Navalny faced a new criminal trial.
The timing of the expulsions of diplomats from Germany, Poland and Sweden seemed intended to send a message both at home and abroad. In the West, the European Union’s foreign policy chief, Josep Borrell Fontelles, had been criticized for going ahead with a trip to Moscow this week despite the jailing of Mr. Navalny, and for playing down the possibility of new sanctions against Russia.
The Kremlin’s decision to expel diplomats from three E.U. member states on the same day as Mr. Borrell’s visit signaled that Russia was not prepared to compromise on the Navalny case. Hours before the Foreign Ministry announced the expulsions, Mr. Borrell called for Mr. Navalny’s freedom at a news conference alongside Russia’s foreign minister, Sergey V. Lavrov.
For Russia’s domestic audience, the expulsions served as the latest example of what the Kremlin has described as Western interference fomenting public discontent. The Foreign Ministry said representatives of Germany, Poland and Sweden had been summoned and notified that three of their embassies’ diplomats had been identified as participants in unauthorized pro-Navalny rallies on Jan. 23.
“It was underscored that such actions from their side are unacceptable and do not accord with their diplomatic status,” the Foreign Ministry said. “They have been ordered to leave the Russian Federation as soon as possible.”
Mr. Borrell “strongly condemned” the expulsions, a spokesman said. Sweden called the expulsion of its diplomat “completely unfounded.” Chancellor Angela Merkel of Germany said she had learned of them during a video conference with President Emmanuel Macron of France on Friday.
“We consider these expulsions to be unjustified and believe them to be another facet of the detachment from the rule of law that can be observed in Russia at this time,” Ms. Merkel said.
Mr. Navalny survived a nerve-agent poisoning in Siberia last summer and recovered in Germany, accusing Mr. Putin of having tried to kill him. Then he returned to Moscow last month despite facing near-certain arrest.
His arrival set off the biggest nationwide anti-Kremlin protests of recent years and brought an enormous crackdown on the opposition, with more than 10,000 arrests in the last three weeks. The Kremlin’s show of force suggests that Mr. Putin sees the longtime gadfly as a significant threat — and that the president will not shy away from bringing the government’s vast resources to bear on stifling dissent.
The Kremlin denies any involvement in Mr. Navalny’s poisoning and says that detentions at unauthorized protests are justified and lawful. On Friday, Mr. Navalny faced a new criminal trial — this time on charges of slandering a war veteran — while his supporters geared up for what they expect to be a yearslong battle against the Kremlin.
The start of the new trial came three days after a different court sentenced Mr. Navalny to two years and eight months in prison for violating his parole on a 2014 embezzlement conviction that Europe’s top human rights court later ruled was politically motivated.
The trial, in which Mr. Navalny is not expected to face more prison time, appeared to be a vehicle for the Kremlin to tie his team up further in the courts while also giving the state news media a fresh opportunity to tar the opposition leader’s image. The slander offense that Mr. Navalny is being tried for was punishable by a fine or community service when he was charged with it last year, though lawmakers have since increased the potential punishment to up to two years in prison.
Prosecutors accuse Mr. Navalny of slandering a World War II veteran in social media posts last year. The posts criticized people who support President Vladimir V. Putin’s constitutional amendments approved last July that allow him to remain in power until 2036.
“You’re using him and his medals to defend Putin the thief and all of his thieving friends,” Mr. Navalny said in court on Friday, according to a recording.
Mr. Navalny can still appeal his prison sentence in the previous trial, and his allies are working to prepare their supporters for a long fight ahead.
One of Mr. Navalny’s top aides, Leonid Volkov, said his camp would not be calling for more street protests in the coming weeks because it needed to regroup before nationwide parliamentary elections that are scheduled for September.
“This is a path that could take several years, but this is our plan,” Mr. Volkov said. “We need to preserve our candidates for the election, and we need to preserve our campaign offices.”
The Navalny camp’s strategy is to build up pressure on the Kremlin and chip away at Mr. Putin’s legitimacy, with the expectation that sooner or later, his authority will collapse amid discontent in the general public and in the ruling elite.
Mr. Navalny’s allies abroad, including Mr. Volkov, are also increasingly engaging with Western governments in the hopes of persuading them to imposed sanctions on people close to Mr. Putin.
“If we keep going out every week, we’ll get thousands more arrested and hundreds more beaten up and the work of the campaign offices will be paralyzed,” Mr. Volkov said. “We will get Aleksei out of prison, first and foremost, using foreign-policy methods.”
Mr. Navalny, in a letter from jail that his team published late Thursday, called on his supporters to keep up the fight.
“The iron doors slam shut behind me with a deafening clang, but I feel like a free man,” Mr. Navalny wrote. “They can hold onto power, using it for personal gain, only by relying on our fear. But we, having overcome fear, can free our homeland from a little bunch of thieving occupiers.”
In court on Friday, Mr. Navalny tried to cast the slander case against him as a narrative concocted by Kremlin propaganda specialists who were seeking to take advantage of the Russian public’s sympathy for World War II veterans.
Mr. Navalny’s offense, according to prosecutors, was a tweet last June in which he described people appearing in a video agitating for Mr. Putin’s constitutional amendments as “traitors,” “people without a conscience.”
One of the people in that video was the veteran Ignat Artemenko, 94, whom prosecutors later picked out as a particular victim of Mr. Navalny’s alleged slander.
Mr. Artemenko appeared in court by video link, but the trial was soon interrupted because he was not feeling well and an ambulance had to be called, according to journalists in the courtroom.
“I told you that they’d need to call an ambulance for him!” Mr. Navalny said.
“Let it be entered into the court record that it was Aleksei Anatolyevich Navalny who brought him to this state,” the prosecutor said.
Steven Erlanger contributed reporting from Brussels, and Melissa Eddy from Berlin.