"According to preliminary reports, 12 bodies have been found," a ministry spokesman said.
The ministry said earlier today one of the passengers had been spotted and rescued.
The accident occurred near Zmeiny Island at about 2:00 p.m. Moscow time (11:00 GMT). The helicopter had taken off from Odessa, Ukraine's largest port. The cause of the accident is not known.
Crashes of Mi-8 Hip transport helicopters, first adopted by the Soviet Air Force in the late 1960s, are a relatively common occurrence in countries that use the aircraft. Three accidents involving the helicopter have occurred this year alone.
A Mi-8 crashed with 11 climbers on board in the former Soviet Central Asian republic of Tajikistan on March 8, killing one person and injuring five others. All 10 UN personnel on board a Mi-8 died when the helicopter crashed in Nepal.
