Rescuers strive to find 16 fishermen missing in Caspian Sea

A rescue operation is continuing in an attempt to save 16 fishermen, whose ships are frozen in the Caspian Sea.

The mission, which started on Saturday, has so far been unable to locate the four boats. 

A plane from Russia and a helicopter from Kazakhstan have been deployed.
 
The fishermen set sail on December 28, and have been stranded for four days.