MOSCOW - One policeman was killed and another injured when a car exploded at a checkpoint in Russia's volatile region of Dagestan Wednesday, local police said, hours after another officer died in a bombing claimed by the Islamic State group.

"As police were trying to stop a car, the driver drove past and the car exploded," local police spokeswoman Fatina Ubaydatova told AFP. "As a result one policeman was killed and one was injured, according to preliminary information."

Ubaydatova said the identity and fate of the people in the vehicle remained unknown.

An unnamed source in law enforcement told RIA Novosti state news agency that a brief car chase ensued after the vehicle failed to stop at the checkpoint and that its occupants hurled an explosive device at the police car.

The incident came hours after a police officer was killed and two were injured when explosive devices were detonated on a main road near Dagestan's city of Kaspiysk late Tuesday as two police vehicles passed.

The Aamaq news agency, which is affiliated with IS, claimed that fighters from the group were behind the bombing.

The officer killed in the Wednesday attack, 35-year-old lieutenant Igor Mutsenik, worked for the police force of Siberia's Krasnoyarsk region but had been temporarily serving in Dagestan.

His body will be sent home within the next few days, authorities said.

Investigators said they had launched a probe into the incident, which the Kremlin refused to comment on.

Ubaydatova said that Russia's national anti-terror committee would be involved in the investigation.

Tuesday's attack is the fourth to be claimed by IS in the North Caucasus in the last seven months, according to Caucasian Knot, a news portal that monitors the region.

Dagestan's police force refused to comment about any possible links between the two incidents in the region, which occurred some 100 kilometres apart.

Attacks against police are not uncommon in the North Caucasus region, which faces a simmering Islamist insurgency.

Last year 126 people were killed in Dagestan as a result of terror and armed conflict, including 13 law enforcement officers, Caucasian Knot reported.

In February, two police officers died and two were injured after attackers detonated a car bomb at a checkpoint. Around a dozen civilians were also injured.

The Islamic State group claimed a deadly shooting in December near the ancient citadel of Derbent, southern Dagestan.

Islamist rebels from Dagestan, which lies immediately east of Chechnya, are known to have travelled to join the Islamic State group. Last year the group declared it had established a "franchise" in the North Caucasus.

Al-Qaeda's affiliate in Syria, the Al-Nusra Front, has previously called on militants from the Caucasus to attack targets in Russia in response to Moscow's bombing campaign in Syria.