The funeral of Alexei Navalny got under way in Moscow Friday in what could turn out to be one of the few remaining avenues for his supporters to vent their anger at President Vladimir Putin as well as mourning one of the few politicians capable of standing up against the Russian leader.

The city was on edge in the hours before the service. Russian independent media reported heavy police presence Friday morning around the church and cemetery where the opposition leader will be laid to rest after he died in an Arctic prison camp last month. Heightened security was also evident around some public buildings and metro stations, residents said.

By noon, crowds had begun to gather at the church where the service was to be held. Fences had been erected outside to control the crowds. Long lines of people waited to pay their respects, many carrying flowers.

The crowd erupted in applause and cries of “Navalny, Navalny” as the hearse carrying his coffin entered the church compound. “You were not afraid and we are not afraid,” they chanted, as mourners were gradually allowed to enter the church.

Navalny’s widow, Yulia Navalnaya , earlier this week warned in a speech to the European Parliament in Strasbourg that Russia’s security forces could use the funeral as an opportunity to round up more of his supporters. At least 400 people were arrested across Russia for laying flowers in memory of Navalny after news of his death emerged on Feb. 16 , according to OVD-Info, a Russian rights-monitoring organization. Navalnaya also told European lawmakers that Putin had killed her husband, an allegation the Kremlin has denied.

“On his orders, Alexei was tortured for three years: he was starved to death in a tiny stone cell, cut off from the outside world, and denied visits, phone calls, and even letters,” she said. “Even after that they abused his body and abused his mother,” she added, without providing evidence.

Associates of Navalny, who was 47 and rose to fame through a series of YouTube investigations exposing the wealth of Putin’s inner circle, earlier indicated that they may try to use his funeral as a way to stir up opposition to Putin’s continued leadership ahead of a presidential election this month that the Russian leader is expected to win easily . Navalny’s media skills set him apart from other figures in Russia’s fragmented opposition and gave him a nationwide following that made him especially dangerous to Putin, whom he once called “a naked, thieving emperor.”

In 2020, Navalny survived a poisoning attempt while returning from a campaign trip to eastern Russia. He nearly died and was evacuated to Germany for treatment after his wife made a public appeal to Putin. He returned to Russia in January 2021 and was detained on arrival at Moscow’s Sheremetyevo airport, and later sentenced to 30 years in prison on various charges.

Presidential spokesman Dmitry Peskov told reporters Friday that the Kremlin had no comment on Navalny’s funeral, but he warned of the consequences of participating in “so-called spontaneous memorials,” the state news agency TASS reported.

“We have a reminder that there is a law [and] it must be followed,” Peskov said. “Any unauthorized gatherings will violate the law. Accordingly, those who participate in them will be held accountable.”

Last week, Navalny’s mother, Lyudmila Navalnaya , released a video saying Russian authorities demanded that he be buried in secret and alleging that authorities attempted to blackmail her and threatened they would “do something with my son’s body.”

Russia’s Investigative Committee, the country’s main investigative authority, didn’t respond to a request for comment on Lyudmila Navalnaya’s claims. Prison authorities reported that Navalny collapsed after a walk at his prison camp, lost consciousness and couldn’t be revived. Russian state media has largely remained silent on Navalny’s death and why he was serving prison time.

After Navalny’s team struggled for days to find a venue that would agree to host his memorial service, his allies said on Thursday that no mortuary had agreed to send a hearse to bring his body to the church for the funeral service. The businesses had reportedly been getting calls from unknown people threatening them not to transport Navalny’s body anywhere, according to Navalny’s spokeswoman, Kira Yarmysh .

The funeral was being held at the Church of the Icon of the Mother of God, in the area where Navalny once lived. Among those attending were the U.S. ambassador to Moscow, Lynne Tracy , who carried some flowers.

Navalny’s death has further frayed relations between Russia and the West, already strained to breaking point over Putin’s invasion of Ukraine two years ago. President Biden placed the blame squarely on Putin, while other members of the Group of Seven advanced economies also laid the blame with the Russian president and demanded that Moscow provide an explanation. This week, the European Parliament adopted a resolution saying that full responsibility for Navalny’s death lies with the Russian state and Putin in particular should be held accountable.

Russia has dismissed the statements as an attempt to interfere in its internal affairs.

Yarmysh said Navalny’s team initially struggled to find a place to hold the memorial service. He will be buried nearby in the Borisov Cemetery. His associates published a diagram on social media with instructions on how to get from the church to the cemetery.

Some of the scenes at the church were being livestreamed on Navalny’s YouTube channel, while his supporters have been urged to lay flowers at memorials in honor of the opposition leader at 7 p.m. local time.

Navalny’s allies have announced a reward of 100,000 euros, equivalent to $108,000, for information that could shed light on Navalny’s death and urged members of the security forces to come forward, saying they would help any informants leave the country.

Navalny’s widow, who has vowed to continue his work, has promised an investigation into his death.

“Putin must answer for what he has done to my country,” she told European lawmakers. “Putin must answer for what he has done to a neighboring, peaceful country. And Putin must answer for everything he has done to Alexei.”

Write to Ann M. Simmons at and Georgi Kantchev at