A bomb blast in the Chechen capital, Grozny, has torn through a stadium crowded with people observing Victory Day celebrations. At least 14 people have been reported killed, including pro-Moscow Chechen President Akhmad Kadyrov.

On a day meant to showcase an historic Russian military victory, Russian television was awash with images of carnage and pandemonium in Grozny, after a bomb exploded in the packed stadium during celebrations commemorating Moscow's victory over Nazi Germany.

Russian President Vladimir Putin himself confirmed that Akhmad Kadyrov, the man the Kremlin backed in the Chechen presidency, had died in the blast. Mr. Putin warned that, as he put it, retribution is unavoidable for terrorists.

Federal investigators have arrived on the scene and are picking through the debris for clues as to the exact cause of the explosion.

There has been no claim of responsibility, but Russian suspicion immediately fell on Chechen separatists, who have been locked in a bitter war with Russia over the territory since 1994.

The blast occurred in a section of the stadium that was reserved for the political and military elite.

There had been conflicting early reports as to whether President Kadyrov had been killed or was among the injured. But hours later, Russian news agencies quoted Russian President Putin and the regional military command as confirming Mr. Kadyrov's death.

Mr. Kadyrov has survived numerous assassination attempts in the past and his death is seen as marking a major setback for the Kremlin's ongoing efforts to portray the situation in Chechnya as normalized.

Earlier, overseeing parallel Victory Day Celebrations in Moscow, President Putin told war veterans there would be certain retribution for, what he called, the terrorist forces Russia is fighting today. But he made no direct reference to the Grozny blast.

Russia's Interfax news agency quotes the Kremlin press service as saying Chechen Prime Minister Sergei Abramov will now act as president of the southern Russian republic, under terms of the Chechen constitution.