Thousands of mourners flocked to Tsentoroi, the settlement in southeastern Chechnya that is home to Kadyrov's clan, Russian media reported. NTV television showed hundreds of people gathered around pallbearers carrying Kadyrov's body, covered by a white woolen shroud.
Funerals were held elsewhere for other victims including Khusein Isayev, the head of Chechnya's State Council, and Reuters photographer Adlan Khasanov.
The blast ripped through a stadium grandstand in the Chechen capital Grozny during Victory Day celebrations marking the anniversary of the Nazi defeat in World War II.
The Grozny emergency medical center said Sunday that 24 people were killed, but Chechnya's Deputy Minister of Emergency Situations, Akhmed Dzheirkhanov, said Monday that six were killed and 57 wounded. Dzheirkhanov said rescuers from the center had counted some of the wounded as dead, and did not confirm Russian media reports of a seventh death overnight.
NTV said 21 people remained hospitalized Monday. Among the wounded was the top Russian military commander in Chechnya, Col.-Gen. Valery Baranov, who had a leg amputated. President Vladimir Putin's representative in southern Russia, Vladimir Yakovlev, said Baranov was conscious Monday and in "satisfactory" condition.
The bombing — which thwarted heavy security in place for official ceremonies nationwide on an important holiday — underlined the difficulties Russia faces in controlling the violence in Chechnya despite a massive troop presence. It was expected to spark new violence between Kadyrov's camp and his enemies, who had long pledged to eliminate him.
The top federal prosecutor in southern Russia, Sergei Fridinsky, suggested whoever was behind the explosion had help from someone with access to the stadium, saying in televised comments that the level of security meant "an outsider could not have come and set off an explosive device." He said investigators would question people involved in security for the event.
Fridinsky said there were many theories about the bombing, but that no suspects had been identified and nobody was detained. Russian media had reported Sunday that five people were detained.
Fridinsky said the blast was caused by an explosive device made out of two artillery shells, one of which did not detonate, and that a third device made of plastic explosives was found nearby. The bomb, which Fridinsky said was put in place some time ago, was planted under the seats where Kadyrov and other dignitaries were watching the ceremonies.
The ITAR-Tass news agency reported that the mine was planted under the concrete floor of the VIP podium, and that investigators were trying to identify people who had worked on the three-month renovation of the stadium, completed just before the holiday.
There was no claim of responsibility, but suspicion inevitably fell on Chechen rebels, who are fighting Russian soldiers as well as Chechen police and security forces employed by the regional government and what was Kadyrov's administration.
Former rebel military leader and Chechen president Aslan Maskhadov condemned the bombing, according to a separatist Web site that quoted him as saying he suspected it was planned by Russian security services "to liquidate the marionette government."
Kadyrov, a former separatist who broke with rebels and with sided with the Kremlin around the time the second of the two wars that have wracked Chechnya in the past decade began, in 1999, had survived assassination attempts before.
Previous major attacks in Chechnya have been followed by massive operations to find the perpetrators, with troops and security forces carrying out intrusive searches and detaining scores of people.
Sunday's attack was expected to increase fear in Chechnya, where Kadyrov's security service, run by his younger son Ramzan, has been accused of being behind civilian disappearances and killings. Both Kadyrovs denied the accusations.
"Justice will take the upper hand and retribution is inevitable," Putin said Sunday, ITAR-Tass reported.
Chechen Prime Minister Sergei Abramov took over as acting president of Chechnya, and Russian news agencies reported Monday that he appointed Ramzan Kadyrov as first deputy chairman of the government. News reports said officials pledged a new presidential election would be held in Chechnya within four months.
But the death of Kadyrov — the key figure in Putin's efforts to wrest control over Chechnya from the rebels and lend legitimacy to Russia's rule — clouded the future.
"This will lead to quite serious changes in the system of rule in the republic, because the system that was formed was built in accordance with (Kadyrov's) methods of controlling the situation," said Shamil Beno, a former separatist Chechen official who now works as human rights activist in Moscow, said on Echo of Moscow radio.
Kadyrov was appointed by the Kremlin as Chechnya's administrator in 2000 and elected president last October in a vote widely criticized as fraudulent.
While he was distrusted by many Chechens and frequently criticized Russian actions in the region, he was a staunch opponent of separatism and a vocal supporter of Putin, who met with Ramzan Kadyrov on Sunday and called the slain president "a really heroic person."