Barricades were emptied near the church where Navalny's memorial service will be held on Friday
With hours remaining until Alexei Navalny's funeral, his team said they were still facing difficulties in organizing the farewell ceremony.
His spokeswoman Kira Yarmysh said they were unable to find a hearse to transport the body to the church.
“Anonymous people call the morgue and threaten it if they accept to take Alexei’s body,” Yarmysh said.
The funeral is scheduled to be held on Friday in Maryino, on the outskirts of Moscow.
The team announced on Wednesday that the memorial service will be held at 14:00 Moscow time (11:00 GMT) in the Church of the Icon of the Virgin Mary Troy My Sorrows.
Burial will then take place in the nearby Borisovskoe cemetery at 16:00.
The funeral service will also be broadcast online on Navalny's YouTube channel.
Navalny died on February 16 in a Russian prison inside the Arctic Circle. He was sentenced to three years in prison on trumped-up charges.
His team, which encouraged people to attend, shared a map of the route between the two locations.
They also shared a list of places abroad – from Seoul to Rome, Montreal and Stockholm – where people can join memorial services for Navalny.
It is unclear how many people will attend the funeral in Moscow on Friday.
Speaking to BBC Newshour, Leonid Volkov, Navalny's former chief of staff, said he was concerned about what might happen while on duty in Moscow.
“I'm afraid that surprises will be expected tomorrow,” he said. “Honestly, as I speak now, I don't know if they will actually allow people to say goodbye to Alexei.”
He added that Navalny's team is also concerned that problems could arise with the church where the service is being held.
In March 2015, thousands lined the streets to pay tribute to slain opposition politician Boris Nemtsov, but any similar public outpouring of grief for an opponent of President Vladimir Putin is unlikely to be permitted now.
In recent years, Russian authorities have cracked down on any action that could be interpreted as criticism of the government. Attempts to commemorate Navalny's death have been met with severe backlash, with temporary monuments removed and hundreds arrested.
Photos circulated on social media Thursday afternoon showed a heavy police presence and barriers waiting to be installed near the church where the memorial service will be held and in the cemetery where Navalny is scheduled to be buried.
The RusNews channel on the Telegram app also said that surveillance cameras had been installed “on every streetlight” surrounding the cemetery.
The first section – a group of lawyers and human rights defenders – shared advice on social media for those planning to go to Navalny's funeral.
She warned that “pro-government activists” were acting as agitators and urged people to remain vigilant: “Arrests after the ceremony cannot be ruled out… Stay under the radar of the security forces – do not use public transport or apply for papers in the days after the funeral.”
The advice also includes not carrying any items bearing Navalny's image or the symbol of his anti-corruption foundation, which Russian authorities have declared an extremist organization.
It is not known which members of Navalny's family will be able to attend the funeral other than his mother Lyudmila, who recently publicly accused authorities of withholding her son's body.
Navalny's children Daria (23 years old) and Zakhar (15 years old) live abroad.
His widow, Yulia, is not believed to currently be living in Russia, but she could risk arrest if she returns due to her work with Navalny's team and her recent public statements blaming Russian President Vladimir Putin for her husband's death.
Authorities have reportedly tried to thwart attempts by Navalny's team to organize a public farewell party for the opposition leader for several days.
Ms. Yarmysh said on Tuesday that Navalny's team was struggling to find a place to hold the concert. She added that some funeral homes claimed to be fully booked, while others told her they were “banned” from working with them.
Navalny's widow, Yulia, said in a speech on Wednesday that she did not know whether the funeral would be peaceful or whether the police would arrest those who came to bid him farewell.