Hundreds of people gathered to bid farewell to dissident Alexei Navalny at a funeral Friday in Moscow under a heavy police presence, following a battle with authorities over the release of his body after his still-unexplained death in an Arctic penal colony.

His supporters said several churches in Moscow refused to hold the service before Navalny’s team got permission from one in the capital’s Maryino district, where he once lived before his 2020 poisoning, treatment in Germany and subsequent arrest on his return to Russia.

The Church of the Icon of the Mother of God Soothe My Sorrows, which was encircled by crowd-control barriers, did not mention the service on its social media page. Hours before the funeral was set to start, hundreds waited to enter the church under the watch of police who deployed in big numbers. Western diplomats were spotted in the long line.

After the hearse arrived at the church, the coffin could be seen on livestreamed footage being taken out of the vehicle, as the crowd applauded and chanted: “Navalny! Navalny!”

Kremlin spokesman Dmitry Peskov urged those gathering in Moscow and other places not to break the law, saying any “unauthorized (mass) gatherings” are violations.

A burial was to follow at the nearby Borisovskoye Cemetery, where police also showed up in force.

Navalny’s mother, Lyudmila Navalnaya, spent eight days trying to get authorities to release the body following his February 16 death at Penal Colony No. 3 in the town of Kharp, in the Yamalo-Nenets region about 1,200 miles northeast of Moscow.

Even on Friday itself, the morgue where the body was being held delayed its release, according to Navalny’s close ally, Ivan Zhdanov,  the director of his Anti-Corruption Foundation.

Authorities originally said they couldn’t turn over the body because they needed to conduct post-mortem tests. Mrs. Navalnaya, 69, made a video appeal to President Putin to release it so she could bury her son with dignity.

Once it was released, at least one funeral director said he had been “forbidden” to work with Navalny’s supporters, his spokeswoman Kira Yarmysh said on social media. They also struggled to find a hearse.

“Unknown people are calling up people and threatening them not to take Alexei’s body anywhere,” Ms. Yarmysh said Thursday.

Russian authorities still haven’t announced the cause of death for Navalny, 47, who crusaded against official corruption and organized big protests as Mr. Putin’s fiercest political foe. Many Western leaders blamed the death on the Russian leader, an accusation the Kremlin angrily rejected.

It was not immediately clear who among Navalny’s family or allies would attend the funeral, with many of his associates in exile abroad due to fear of prosecution in Russia. Navalny’s Foundation for Fighting Corruption and his regional offices were designated as “extremist organizations” by the Russian government in 2021.

The funeral is streamed live on Navalny’s YouTube channel.

His widow, Yulia Navalnaya, accused Mr. Putin and Moscow’s mayor Sergei Sobyanin of trying to block a public funeral.

“We don’t want any special treatment — just to give people the opportunity to say farewell to Alexei in a normal way,” Yulia Navalnaya wrote on X, the platform formerly known as Twitter. In a speech to European lawmakers on Wednesday in Strasbourg, France, she also expressed fears that police might interfere with the gathering or would “arrest those who have come to say goodbye to my husband.”

Moscow authorities refused permission for a separate memorial event for Navalny and slain opposition leader Boris Nemtsov on Friday, citing Covid restrictions, according to politician Yekaterina Duntsova said. Nemtsov, a 55-year-old former deputy prime minister, was shot to death as he walked on a bridge adjacent to the Kremlin on the night of February 27, 2015.

Ms. Yarmysh also urged Navalny’s supporters around the world to lay flowers in his honor Friday.

“Everyone who knew Alexei says what a cheerful, courageous and honest person he was,” Ms. Yarmysh said Thursday. “But the greater truth is that even if you never met Alexei, you knew what he was like, too. You shared his investigations, you went to rallies with him, you read his posts from prison. His example showed many people what to do when even when things were scary and difficult.”

Mr. Zhdanov, the Navalny ally, said that the funeral had initially been planned for Thursday — the day of Mr. Putin’s annual state-of-the-nation address — but no venue agreed to hold it then.

In an interview with the independent Russian news site Meduza, Mr. Zhdanov said authorities had pressured Navalny’s relatives to “have a quiet family funeral.”