The death toll among Kazakh servicemen swept into the Caspian Sea during a naval military exercise has risen to 12, the administration of Kazakhstan's Mangystau Region said Thursday.

According to updated information, 17 servicemen were swept out to sea while carrying out a combat training task after weather conditions deteriorated sharply and winds intensified, The Caspian Post reports, citing Anadolu Agency.

Twelve servicemen died, three were rescued, and the search for two others remains underway, the regional administration said.

Kazakhstan's Defense Ministry had earlier reported that servicemen were swept into the sea while conducting a combat training mission in the southwestern part of Mangystau Region. The incident followed a "sudden deterioration in weather conditions and intensifying winds," the ministry said.

The Defense Ministry initially said that, according to preliminary information, 19 servicemen had been swept out to sea. It reported that three had been rescued and that search and rescue operations for the remaining personnel were continuing.

A commission headed by Defense Minister Dauren Kosanov was urgently sent to the scene to determine the circumstances of the incident and oversee search and rescue operations, the ministry said.

It added that further information on the search operation and the condition of the servicemen would be released as data was received and verified.

Kazakh President Kassym-Jomart Tokayev declared September 25 a national day of mourning in memory of the servicemen who died.