(Bloomberg) -- Alexey Navalny’s widow said she’ll continue his fight against Russian President Vladimir Putin as she met with top European Union officials weighing fresh sanctions over the Kremlin critic’s death.

“The main thing we can do now for Alexey and for ourselves is to keep up the fight,” Yulia Navalnaya said in a video address to his supporters posted Monday on social media. “Fight and don’t give up. I’m not afraid, and you shouldn’t be afraid of anything.”

EU foreign affairs chief Josep Borrell said earlier Monday that Navalnaya would attend a meeting of the bloc’s foreign ministers in Brussels to give a “message about how to support the political opposition inside Russia.” Member states will “for sure” propose sanctions against Russia, he said. 

Putin has made no comment on the death of his most formidable domestic opponent in a remote Arctic prison since it was announced Friday. US President Joe Biden has said “Putin is responsible” for Navalny’s death, which happened as the Russian president is preparing to gain a fifth term in March elections in which he faces no serious competition. 

European Commission President Ursula von der Leyen said the death of the imprisoned opposition leader displayed the “ruthlessness and perfidy” of Putin and his regime, noting that Navalny’s widow said he was in good health. “So everything indicates, and what she said really confirmed that, that he was deliberately murdered,” von der Leyen told reporters in Berlin on Monday.

News of the fatality came as a surprise to officials working in the Kremlin, according to a person familiar with the matter. It’s unlikely Navalny’s wife will be able to lead the opposition or represent a challenge, the person said.

Officials haven’t given a cause of death for 47-year-old Navalny at the IK-3 prison colony in Russia’s northern Yamalo-Nenets region, while local authorities continue to bar his family from even viewing his body. 

Navalny’s spokeswoman, Kira Yarmysh, said his mother and lawyers were prevented from entering the Salekhard morgue nearest the prison on Monday and staff refused to say whether the body was being held there. Investigators said a “chemical examination” would be conducted on the body for another 14 days, she said. 

Under Russian law, authorities are required to transfer the body of a deceased person to family representatives within 48 hours once the cause of death has been established. There’s no time limit on an investigation.

Authorities are taking every action necessary to investigate the circumstances of the death, Kremlin spokesman Dmitry Peskov told reporters Monday, according to the Interfax news service.

Police detained at least 400 people over the weekend as they tried to lay flowers at makeshift memorials to Navalny in Moscow and other cities, in spite of the atmosphere of fear created by an intensifying Kremlin crackdown on protests since Putin ordered the February 2022 invasion of Ukraine. 

“If she has decided to engage in political activity, then I will definitely support her,” self-exiled oligarch Mikhail Khodorkovsky said of Navalnaya, adding that he favored a coalition of opposition groups with “Yulia as one of the leaders.”

Biden told reporters at the White House Friday that “we’re looking at a whole number of options” in response to Navalny’s death, though he stopped short of announcing any measures against Russia. 

“Russian authorities and President Putin personally bear full responsibility for this death,” Swedish Prime Minister Ulf Kristersson told a news conference Monday with his Polish counterpart Donald Tusk in Warsaw.

Russia’s opposition, which ranges from liberals to ultra-nationalists who support the invasion of Ukraine, has long been beset by internal squabbling. Navalny’s death robbed the anti-Kremlin forces of a leader with the standing and charisma to unify them. 

Why Alexey Navalny Was Putin’s Domestic Enemy No. 1: QuickTake

While she often appeared at his side during protests in Russia, Navalnaya, 47, kept mostly in the shadows after her husband’s imprisonment. Now living in Germany, she faces an uphill battle to unite the fragmented opposition behind her.

In June last year, Navalny’s allies boycotted a meeting of Western-backed opposition leaders in Brussels, cementing divisions within the pro-democracy movement.

Navalnaya traveled to Russia from Germany with her husband in January 2021 following his treatment for nerve-agent poisoning in Siberia that he and the West blamed on the Kremlin, which denied involvement. Their embrace at the airport as police arrested him at passport control was their last free moment together.

--With assistance from John Follain, Henry Meyer and Katharina Rosskopf.

(Updates with spokeswoman’s comments in eighth paragraph.)

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