Thousands of mourners have attended the funeral of Chechen President Akhmad Kadyrov after his assassination in a bomb attack in Grozny on Sunday.
Three days of mourning have been declared to honour Akhmad Kadyrov
Mr Kadyrov was a key ally for Russian President Vladimir Putin, who has vowed revenge for the attack.
Chechen Prime Minister Sergei Abramov has taken over as leader while Mr Kadyrov's son Ramzan has been made deputy head of the Chechen government.
Ramzan leads a militia that has been accused of human rights abuses.
The BBC's Damian Grammaticas says his appointment may simply fuel Chechnya's bloody conflict.
The Chechen separatist leader, Aslan Maskhadov, has denied any involvement in the attack, which happened during a ceremony marking victory in World War II.
The bomb went off in a VIP seating area of the packed Dynamo stadium in Grozny.
The estimated death toll varies between six and 30, with around 50 injured. At least two other senior Chechen officials were among the dead, and a commander of Russian forces in the region is in intensive care in hospital with serious injuries.
In Mr Kadyrov's home village of Tsentoroi, 50 km (30 miles) southeast of Grozny, shops were closed and thousands of mourners marched through the streets chanting prayers.
Mr Kadyrov's two sons Ramzan and Zelimkhan helped carry their father's body, covered in a white cloth, on a raised stretcher in accordance with Chechen tradition.
Three days of mourning have been declared in the region.
Chechen Prime Minister Sergey Abramov paid tribute to Mr Kadyrov, speaking of the president's hopes for Chechnya.
"We spoke about how we will build the towns, how we and you will restore the economy, establish peaceful life, but I can say one thing - that he was counting on all of you," he said.
Security forces throughout Chechnya have been placed on high alert and Russia's Itar-Tass news agency has reported that five people have already been detained on suspicion of involvement with the attack, according to interior ministry officials.
Russian Federation Council member General Aleksandr Kalita has called for tough measures to be taken against Chechen rebels.
"It's time to stop flirting with the rebels and hoping they include some people with a conscience," he told Moscow radio.
Born in Kazakhstan in 1951
Studied Islam and became Chechnya's mufti in 1995
Sacked as mufti in 1999 after falling out with separatist leader Aslan Maskhadov
Appointed as head of pro-Moscow administration by President Putin
"Precise military operations must be carried out to destroy the gangsters and they shouldn't be called anything else."
Officials say the bomb that killed Mr Kadyrov was made out of a 152mm artillery shell and detonated with a wire or timer.
Chechnya's acting prosecutor Vladimir Kravcheko said the bomb had been placed inside a concrete part of the stadium which meant it escaped detection in security sweeps.
"Everything points to a well-planned terrorist act, prepared over a long period of time, not just a few days," he said.
Russia has been fighting separatists in Chechnya since the republic first tried to break away in the 1990s.
Moscow has reimposed its rule in Grozny, but rebel attacks have continued, both in Chechnya and elsewhere in Russia.
Mr Kadyrov's assassination has drawn broad international condemnation.
A White House spokesman said Washington resolutely rejected all acts of terrorism, while the European Commission described the blast as a " heinous attack".