A policeman was killed Wednesday in Russia's restive region of Dagestan when a man being pursued by police blew himself up in his car, the National Anti-Terrorism Committee said.

The explosion happened hours after an explosion Tuesday night struck a passing police convoy in Dagestan, killing one officer and wounding four others.

Dagestan has become the epicenter of an Islamic insurgency in Russia following two separatist wars in neighboring Chechnya. For more than a decade, Dagestan has suffered bombings, attacks on police and kidnappings blamed on Islamic militants.

The anti-terrorism committee said a police unit tried to stop a suspicious automobile on the outskirts of the village of Sirtych, about 25 kilometers (15 miles) from the border with Azerbaijan. The car's driver, "recognizing the hopelessness of getting away," detonated a bomb that killed both the driver and one policeman, the committee said in a statement.

Earlier, Dagestan police spokeswoman Fatina Ubaydatova said a bomb detonated Tuesday night as a convoy carrying reinforcements of federal police was traveling south of the regional capital of Makhachkala. Federal police are regularly deployed to Dagestan to aid local forces.

The Aamaq news agency, which affiliated with the Islamic State group, said Wednesday that IS fighters carried out that attack. The claim could not be immediately verified.

Investigators at the scene of Tuesday night's attack said they found three more bombs planted on the side of the targeted road Wednesday.

Violence in Dagestan had eased as law enforcement agencies imposed tougher security measures ahead of the 2014 Winter Olympics in Sochi, and many militants are believed to have left for Syria to fight alongside Islamic State extremists there.

Russian authorities estimate that most of the 3,000 Russians believed to have traveled to Syria to join IS forces come from Dagestan.