KARABULAK: Two police officers were killed Monday when a suicide bomber attacked a police station in Russia's volatile North Caucasus region of Ingushetia, officials said.

The deadly attack came after a wave of suicide bombings killed more than 50 Russians last week, prompting the government to promise tougher measures against the Islamist insurgency in the North Caucasus.

The attacker blew himself up outside the local police headquarters in the Ingush town of Karabulak at about 8:20 am (0420 GMT), Russia's investigative committee said in a statement.

"As a result of the blast, the suicide bomber died at the scene and three police officers were taken to hospital, where two of them died," it said, adding that the bomber struck as a car full of officers was entering the compound.

A second explosion that went off outside the Karabulak police station less than an hour later was triggered by a police bomb squad and caused no casualties, a law enforcement source told AFP.

Following the blasts, dozens of police stood near the police station, a drab two-storey building surrounded by metal fences and concrete barriers, an AFP reporter witnessed while visiting Karabulak on Monday morning.

The suicide bomber had been trying to enter the compound and detonated his explosives when guards forced him to stop, a spokesman for the regional interior ministry told ITAR-TASS news agency.

"The terrorist was apparently trying to enter the territory of the police station and trigger an explosion during the morning gathering, which would have led to many deaths," the spokesman was quoted as saying.

Ingushetia is a predominantly Muslim province of Russia's North Caucasus which neighbours war-torn Chechnya and has been troubled in recent years by a violent Islamist insurgency.

The Russian government has sought to tighten security and boost efforts to hunt down insurgents since a pair of suicide bombers attacked the Moscow metro last week, killing 40 people.

That was followed by suicide bombings in the Dagestan region of the North Caucasus that killed 12 people, including a local police chief.

The so-called "Caucasus Emirate," an Islamist group led by Chechen rebel warlord Doku Umarov, has claimed responsibility for the metro attacks.