MOSCOW, April 11, (RAPSI) – A criminal case has been opened after an attack on a rural police station in Stavropol region in southern Russia, reads a statement released on Monday by the Investigative Committee.

Three attackers attempted to enter the police station using grenades. Two of the men were killed in gunfire, one another blew himself up, according to the Investigative Committee.

No police officers or civilians were reportedly killed in the attack. “Technical damage was done to the police station and nearby cars,” the statement reads.

The counter-terrorist operation regime was introduced in the region after the attack, the press service of the Russian Federal Security Service in Stavropol said to TASS news agency.

"In accordance with federal law, a decision was made to conduct a counter-terrorist operation on the territory of Novoseletsky municipal district at 11am Moscow time. The operation is controlled by the National Counter-terrorism Committee," the press service added. Security forces had sealed off the area around the attack and were working to establish the attackers' identities, Russia's National Counter-terrorism Committee told Interfax.

Rapid deployment units, security forces, law and order agencies, and bomb-disposal experts have been reportedly put on high alert.

After the attack had been reported, nearby schools and hospitals were evacuated. Additional security measures were introduced across the region, news agencies quoted Stavropol Governor Vladimir Vladimirov as saying.

It remains unknown whether or not the attackers were members of an Islamic State (IS), an organization prohibited in Russia. IS has vowed revenge after Russia launched a bombing campaign in Syria last September. In November, a Russian passenger jet was blown up over Egypt by a bomb planted by an Islamic State affiliate. In December, the IS has claimed responsibility for a deadly shooting in Derbent, a city in the North Caucacus republic of Dagestan.