Nine rebels preparing to attack Russia were killed on Saturday in Dagestan, the volatile democracy of the Russian Caucasus, the Russian National Anti-Terrorism Commission said.
A "counter-terrorism" operation was launched on Saturday in Derbent, Dagestan, after authorities learned that "malicious elements" were hiding in the city and preparing to attack Labor Day, a holiday in Russia, the commission said in a statement.
"Nine criminals were neutralized after a brief exchange of fire" with law enforcement, it said.
A police officer, a member of a special forces unit, was wounded in the operation, according to the same source.
Dagestan, which borders Chechnya and has a predominantly Muslim population, is one of Russia's poorest and most volatile regions.
Islamic State (IS) jihadist group, which has been sworn in by Islamist guerrillas operating in the Russian Caucasus in June 2015, is often the target of attacks.