At least 18 people died on Friday when a bus carrying construction workers fell into the Black Sea, the Russian Emergencies Ministry said.
The ministry said more than 30 workers were also injured in the incident.
It said the bus was carrying construction workers, who were building a pier in the village of Volna for the oil-and-gas company Tamanneftegaz.
Rescue efforts were ongoing at the site, it added.
According to the official TASS news agency, an investigative committee has launched a criminal case over the crash.
