MOSCOW — Shamil Basayev, the Chechen separatist leader who claimed responsibility for spectacular attacks that killed hundreds of Russian civilians over the last decade, died when a truck carrying dynamite blew up, Russian officials and a rebel website said Monday.
Basayev, labeled by Russian authorities as the country's most wanted criminal, had argued that civilians were legitimate targets because they supported Moscow's war against separatists in the republic of Chechnya.
He claimed responsibility for the 1995 kidnapping of about 1,500 hostages at a hospital in Budyonnovsk, the seizure of a Moscow theater containing about 800 people in 2002 and the siege of a school in Beslan two years ago. At least 371 people, half of them children, died in the shootout that ended that siege.
Russia's security chief, Nikolai P. Patrushev, said Basayev and other Chechen insurgents had been planning a terrorist attack to "put political pressure on Russia's leadership" during the three-day summit of leaders from the world's leading industrialized nations, including President Bush, which is scheduled to begin Saturday in St. Petersburg.
Russian authorities hailed Basayev's death. Pro-Kremlin politicians were among those predicting that his demise would help stabilize Chechnya by depriving the rebels of an audacious leader. Other analysts disputed that, saying the long and bloody resistance to Russian rule there would continue.
In televised remarks, President Vladimir V. Putin called Basayev's death "just retribution against these terrorists, for our children in Beslan, Budyonnovsk, and for all the terrorist acts they carried out in Moscow and other regions of Russia, including in Ingushetia and Chechnya."
Basayev's death marked an enormous political victory for Putin, who has pledged since he took office seven years ago to hunt down the Chechen rebel leaders.
"We will pursue the terrorists everywhere," Putin said early on in his rise to power. "You will forgive me, but if we catch them on the toilet, we will wipe them out in the outhouse."
Russia's NTV television said Basayev's death held a significance for Russia similar to what killing Al Qaeda leader Osama bin Laden would mean for the United States.
Whether Russian action actually led to Basayev's demise remained unclear.
Patrushev said the explosion that killed the Chechen leader took place during a special operation conducted in the village of Ekazhevo, in the Russian republic of Ingushetia, which borders Chechnya.
A statement on a rebel website confirmed Basayev's death but said he was killed "when a truck carrying explosives spontaneously blew up," not as the result of a Russian operation.
An NTV correspondent reporting from Ekazhevo said that residents of the village heard a loud explosion while watching the World Cup soccer championship Sunday night. Then they heard what sounded like shooting and more explosions, he reported.
Ingush Deputy Prime Minister Bashir Aushev told the Russian news agency Interfax that Basayev had been sitting in one of several cars near the truck that exploded. His body was identified "through some of the fragments, including his head," Aushev said.
Fragments of Basayev's prosthetic leg were also found, authorities said.
Analysts differed on whether Basayev's death would curtail the violence in Chechnya and other parts of the troubled Caucasus region of southern Russia.
The death of Basayev "is going to boost the credibility of President Putin as a successful terrorist fighter. This is something that has always been very important to him domestically and internationally," said Dmitry Trenin, deputy director of the Carnegie Moscow Center.
"I think this will be a major symbolic blow to terrorists in Chechnya, and I think that would lead to greater pacification.... This is a milestone," Trenin said.
Ramzan Kadyrov, Chechnya's pro-Moscow prime minister, whose own security forces have frequently been accused of human rights violations, predicted that Basayev's elimination would severely weaken the remaining guerrilla units fighting his government
"Even those people who have not yet realized the perniciousness of this path will understand that their actions have no future," Kadyrov said.
Kadyrov, whose father, Akhmad Kadyrov, was killed in a bombing at a sports stadium in May 2004 for which Basayev claimed responsibility, expressed regret that he had not been able to play a role in killing Basayev.
"I rejoice at Basayev's killing, yet I regret that this monster left this world not with my help," Kadyrov told Interfax.
"I dreamed of strangling him with my own hands.... He was a jackal and died like a jackal, and his body was collected piece by piece. Basayev was not just the No. 1 terrorist. He was my personal enemy."