The death toll from flash floods in Russia's southern Krasnodar region has risen to 134 from 103, police have said.
The worst hit area was Krymsk region, where 123 people died, a police representative at the disaster's emergency task force in Moscow said.
Others died in the Black Sea resort town of Gelendzhik and in the port city of Novorossiisk.
Torrential rains dropped nearly a foot of water in the Black Sea region overnight.
The water rushed into the area around the hard-hit town of Krimsk with such speed and volume that rumours emerged that local officials had opened a nearby water reservoir.
Muddy water coursed through streets and homes, in some cases high enough to flow over the hoods of cars and even as high as rooftops, according to witnesses.
People waded through waist-high water or maneuvered the streets in boats on Saturday.
About 5,000 residences were flooded, the Krasnodar governor was quoted as telling the Interfax news agency.
"Nobody remembers such a flood in all (of the area's) history," Alexander Tkachev said.
Five people died of electrical shock in the Black Sea coastal city of Gelendzhik after a transformer fell into the water, state news agency RIA Novosti said.
Anna Kovalevskaya, whose parents live in the flooded area, described water indundating their home up to the roof.
"In the town people are saying that a reservoir in the mountains above was opened," she told the Moscow-based radio station Russian News Service. "A wave came from there. There was seven meters (22 feet) of water in the town."
There was no immediate official comment on the reservoir speculation.
Ecologist Igor Chestin, director of the Russian office of the World Wildlife Fund acknowledged the rumours, but told the Interfax news agency that "we don't have such information."
State news channel Rossiya 24 showed video of residents rescuing people in small, inflatable boats and others slogging glumly through flooded homes.
As of 10am, more than 28 centimetres (11 inches) of rain had fallen in Gelendzhik since the previous evening, the state meteorological service said.
Gelendzhik is on the Black Sea coast, and along with the area around it, is a popular summer vacation spot, including many children's camps.
Vice-premier Olga Golodets told RIA Novosti that some 7,100 children were at holiday camps in the area, and that with 459 children had to be evacuated.
The area also includes Novorossiisk, a major Black Sea port.
The Transneft oil company said it has suspended loading oil onto tankers at the port because of the severe weather.
More than 1,500 Emergency Ministry officials were working to aid flood victims and clean up the damage, state TV said.
Prime Minister Dmitry Medvedev has set up a commission to help the victims.
