Russia's Emergency Situations Minister says authorities have failed to properly warn residents in the Black Sea region of upcoming floods that killed at least 171 people.

Torrential rain and flooding Saturday turned streets of Krymsk and adjacent towns into swirling muddy rivers and inundated thousands of homes as many residents were sleeping.

Russian news agencies on Monday quoted Vladimir Puchkov as saying that his ministry issued flood warnings but they were insufficient to reach everyone on time.

Russian newspapers quote some local residents saying they did not receive such warnings before the flooding.

Russia has seen a series of natural and man-made disasters in recent years, many of them blamed on aging infrastructure or lax safety rules.