Floods killed four people and prompted the evacuation of 1,500 others on Wednesday in the southern Russian province of Krasnodar, officials said, only weeks after a flash flood killed 171 people there.
Heavy rain overnight caused a river to burst its banks, flooding several hundred homes in the town of Novomikhailovsky and causing power outages in a neighboring town, the Emergency Situations Ministry said.
President Vladimir Putin, accused in the past of reacting too slowly to disasters, urged emergency officials to take all necessary measures to assist those affected.
The Interior Ministry said four people had been killed and 1,500 people had been evacuated, including patients at a hospital. The regional administration's website said three people were missing and that power was out in the affected area.
At least one of the dead was a visitor to the area, a popular vacation destination near the Black Sea shore, regional authorities said.
Krasnodar governor Alexander Tkachev said in a statement the evacuation had been timely and that an emergency warning system had worked effectively.
But the Interfax news agency quoted residents as saying warning sirens could not be heard through the rain.
"There was no notice whatsoever," a person with the Twitter account @inconsta wrote on the social network, saying that cars were floating in the water and a bridge had been destroyed by the floods.
Prosecutors will look into the local authorities' handling of the emergency, the federal Prosecutor General's Office said in a statement.
Authorities were criticized over a lack of preparedness and a slow response to the flash flood on July 7, which devastated the town of Krymsk. Several officials were sacked and detained after the disaster.
Residents of the mountain town of 57,000 were caught by surprise when water poured into their homes and had little time to flee to safety.
Putin, in power since 2000 and back in the presidency since May after four years as prime minister, has visited the area three times since the July flooding, reassuring residents they would receive new or repaired homes.
He accused local officials of negligence after Russia's top investigator said only 52 Krymsk residents had received an official warning about the imminent flooding.
Putin weathered the biggest protests to his 12 years in power over the winter. Active opposition has mainly been confined to big cities and the president is eager not to let it spill into the regions, where he enjoys strong support.