The death toll is rising in a four-day Russian operation to wipe out militants in the Caucasus.

Officials said Saturday 17 police officers have died in the operation with another 24 wounded.

The fighting has been concentrated in the republics of Chechnya and Dagestan, where Islamist insurgents have been battling Russian forces following two separatist wars waged by Chechen rebels.

On Friday, Moscow-backed Chechen leader Ramzan Kadyrov said special operation forces had wiped out an entire group of militants in part of Dagestan. But he also said “full-scale” special operations against militants would continue.

The Associated Press reports Russian officials said on Friday that 20 rebels had been killed.