MOSCOW, May 9 (Reuters) - An explosion ripped through a Victory Day parade in southern Russia on Thursday killing 25 people, including six children, and President Vladimir Putin described the attackers as "scum" who should be treated like Nazis.
He blamed the landmine attack on terrorists, the usual Kremlin term to describe separatist rebels in Chechnya, which borders the province of Dagestan where Thursday's attack took place.
"This crime was carried out by scum who hold nothing sacred," a solemn Putin told a Kremlin gathering after the main parade in Moscow's Red Square to mark the defeat of Nazi Germany 57 years ago.
"We have every right to treat them as Nazis, whose sole aim was to spread death, sow fear and to murder,"
News agencies and local television quoted police as saying 25 people were killed in the attack. Police also said more than 100 people were hurt, 50 of them seriously, in the blast -- the bloodiest since a series of bombings in the southern Russian town of Mineralnye Vody in March 2001 killed 23 people.
Pictures broadcast by the private NTV channel showed wrecked drums and musical instruments scattered across a blood covered street in Kaspiisk, a town some 20 km (12 miles) south of the Dagestan capital.
Its correspondent Ruslan Gusarev said the band was on foot, not in a bus as initial reports suggested, and surrounded by crowds of children and World War Two veterans when the blast erupted.
"The scene is horrifying. There are body parts everywhere and an overpowering smell of blood," he told the private channel by telephone.
TERRORIST THREAT
The blast came just before Putin addressed the traditional Victory Day parade outside the towering walls of the Kremlin, urging the nation to unite to defeat the common threat of terrorism as it had done to crush Adolf Hitler.
"Only by uniting the effort of the people and the state can we confront these threats," Putin said.
"That was well proven by the anti-Hitler coalition. The coalition countries defeated the enemy. And today, we are again uniting and finding allies against a common threat.
"Its name is terrorism."
He summoned security chiefs to the Kremlin and ordered head of the FSB domestic intelligence agency, Nikolai Patrushev, to lead an investigation into the attack.
An Emergencies Ministry spokeswoman in Moscow said at least six children were among the victims of a radio-controlled landmine hidden in bushes which exploded as a marine infantry band marched to the town's Victory Day parade.
Unconfirmed reports said the death toll could rise to 30.
"Nobody doubts that this was a terrorist act," Putin said after meeting his top security officials.
"In the shortest possible time, we will find, convict and punish the criminals," the presidency quoted Putin as saying.
Dagestan is no stranger to violence, bordering Chechnya where Russian troops returned in 1999 in an "anti-terrorist" drive to restore Moscow's control over the rebellious region.
MAY DAY CARNAGE
The May 9 Victory Day parade is the most important public holiday in Russia.
The conflict cost the lives of 27 million people in the Soviet Union and the victory remains one of the few achievements of the Communist era which continues to unite Russia, a vast and often fractious country.
"Today, people intended to mark a holiday of life and justice," said Dagestan's leader Magomedali Magomedov.
"But the scoundrels have turned this into an act of vandalism. They must be destroyed as traitors who are not letting humanity live," Interfax quoted him as saying.
"A war was declared today not only on the law enforcement agencies...(but) on an entire nation. And the will surely emerge as the victor of this war," he added.
Bombs have rocked Russian regions, mostly those close to Chechnya, since Moscow sent troops back into the secessionist province in 1999 to bring it back to its fold.
Although the authorities say the military phase of that operation is over, Russia continues to lose soldiers almost daily in ambushes and bomb attacks.
On April 28, seven people died in a bomb attack on a market in Vladikavkaz, the capital of North Ossetia which also borders Chechnya. Last November, five people died in an explosion in the same city. In July 2000, another five people were killed in two blasts in provinces bordering Chechnya.
The authorities have routinely blamed the blasts on separatist guerrillas.