Investigators launched Sunday a probe into possible negligence after flash floods in southern Russia killed at least 171 people and President Vladimir Putin demanded an explanation from officials.

First funerals were held in the town of Krymsk, the worst hit area in southern Krasnodar region, as emergency workers pulled more bodies from the debris and survivors insisted they had not received any flood warning.

Some bodies were taken from Krymsk after the Saturday flood to morgues in other cities because the town's morgue quickly overflowed, grieving relatives told AFP Sunday at a funeral service held for a local man.

Putin demanded Saturday evening that officials explain the massive death toll in what is the first major disaster since he returned to the Kremlin for a third term in May.

However Putin, who compared the force of water to a "tsunami", also quickly moved to dispel rumours that the deluge might have been caused by an emergency opening of sluice gates at a local reservoir.

Russia's Investigative Committee said Sunday it has launched a criminal probe into possible negligence that has caused people's deaths after Putin called for an investigation to see "who acted how."

At least 171 people died in the disaster, including 12 in the port of Novorossiisk and the popular Black Sea resort town of Gelendzhik where five were electrocuted, a police official with the emergency task force in Moscow told AFP.

The worst hit area was a district around Krymsk with population of about 57,000 where rescue teams have found 159 bodies including three children, police said.

Most of the victims were pensioners, many caught by the floods in their sleep. The disaster damaged properties of 24,000 people, Krasnodar Governor Alexander Tkachev said, according to his press service.

Krymsk is about 200 kilometres (120 miles) northwest of the Black Sea resort of Sochi where Russia will host the 2014 Winter Olympic Games.

Flash floods frequently batter towns along the picturesque Black Sea coast during seasonal rains in the Caucasus mountains, but authorities said the current disaster is unprecedented as they struggled to explain the massive toll, saying only that many people may have been caught offguard.

The force of the water was so ferocious that many residents said they suspected the floods were caused by a release of water at a local reservoir on the Neberdzhai River.

Putin, wearing a black shirt, was shown on television Saturday evening grilling officials about whether an emergency release of water was possible.

"Where did the water come from?" Putin asked government officials in televised remarks.

Governor Tkachev swiftly replied: "It was raining."

On Sunday Tkachev faced a crowd of angry people as he tried to fend off charges that the government had not done its job properly and sought to explain it was simply impossible to notify each and everyone.

"It's like an earthquake. It's impossible to predict it. Do you think it was man-made?" Tkachev asked the crowd in televised remarks Sunday. "Yes!" the people cried back.

He had earlier called on people to stop spreading "stupid rumours," saying the region was pelted with five months' worth of rain.

Investigators acknowledged Sunday that repeated releases of water did happen but it remained unclear whether it might have contributed to the disaster.

Some residents bluntly accused authorities of a cover-up.

"It always rains here but we've never had this before. A seven-metre tall wave crushed everything," Irina Morgunova told AFP in Krymsk. "That is not rain. But no-one will ever say it out loud."

As they tried to sort out their muddy belongings, Krymsk residents also complained they have been left to their own devices and authorities offered little help.

"It's a catastrophe," said Viktor Voloshin, who arrived in the flood-ravaged town Sunday to help relatives whose house was damaged.

"People need drinking water but there is no drinking water being distributed," he told AFP.

"We have 30-degree weather now, diseases will begin," he added.

Volunteers in Moscow and other cities meanwhile mobilised on Russian social networks and Twitter, sending donations and volunteers to Krymsk to help in the crisis.

Putin said survivors would get new homes while families of victims would receive two million rubles ($60,800) each.

The Kremlin declared a national day of mourning Monday, recommending that all entertainment programming be pulled from state television channels.

Photo By Mikhail Mordasov