Four suicide bombers carried out explosions in a village in Russia's Stavropol region, close to the North Caucasus, police said.
Three of the suicide bombers were killed by the blasts, one was shot and killed, Russia's state news agency TASS reported on Monday. No one else was hurt in the attacks.
"Three militants were killed as they attempted to attack the police station. The regional Interior Ministry also confirmed that civilians and law enforcement officers were not hurt," TASS reported.
"The incident has all characteristics of a terrorist attack," TASS said, adding that the attackers have not been identified yet.
Shooting at the building
"We were holding a meeting in the morning when five explosions went off," Sergei Karamyshev, a senior police officer in the village of Novoselitskoye in the southern Stavropol region, told AFP news agency.
"Three people blew themselves up after an officer on duty at the entrance blocked the door to the building," Karamyshev said.
He said that in all there were five explosions: the three suicide bombers and one grenade, but that the cause of the fifth blast was not immediately known.
A spokeswoman for police in the Stavropol region said one of the attackers had died by detonating an explosive device, while two others were killed by "return fire".
"They were shooting at the building," Natalya Tyncherova told AFP, adding that the exact number of attackers was still unclear.
The city is located in the northern tip of Russia's North Caucasus Mountains, where authorities have struggled with homegrown armed groups for decades.
In December, the Islamic State of Iraq and the Levant (ISIL) claimed responsibility for a deadly shooting in Derbent, a city in the North Caucasus republic of Dagestan with an ancient citadel that is popular with tourists.