RIA Novosti said the men had recently returned from the border area of Afghanistan and Pakistan and had received training to carry out a terrorist attack. The three men were Russian citizens, the Russian National Anti-Terrorism Committee said.
"The militants were besieged in the course of a special operation, but opened fire after they were asked to surrender. Two of them were killed and another detained as a result of a rapid shootout," the committee said in a statement, adding one police officer was wounded in the operation.
The government did not release further details on the suspects' plans.