A car packed with explosives blew up as police gave chase, and a bomber in a police uniform set off a second blast in a crowd of police who rushed to the scene, authorities said.

The coordinated attack in the town of Kizlyar, in Dagestan region close to its border with Chechnya, was the latest outbreak in a surge of violence in the Caucasus a decade after the Kremlin’s second of two wars against Chechen separatists.

The Dagestan bombings came 48 hours after Moscow was hit by its bloodiest attack in six years — twin morning rush-hour blasts that killed 39. Authorities blamed women suicide bombers with connections to the mainly North Caucasus.

Prime Minister Vladimir Putin said a single group could be behind the bombings in both Moscow and Dagestan.

“Yet another terrorist act has been committed. I do not rule out that it is one and the same gang acting,” he told a government meeting.

He called the attacks “a crime against Russia” and ordered Interior Minister Rashid Nurgaliyev to bolster the police presence in the North Caucasus.

The blast in Kizlyar took place when a car packed with explosives blew up after its driver ignored a command to halt and sped toward the center of town with police close behind, Nurgaliyev, the interior minister, said in televised comments.

The vehicle — a black four-wheel-drive Niva — exploded with the force of as much as 200 kilograms of TNT, Russian news agencies quoted prosecutorial investigators as saying. Two police officers were killed, Nurgaliyev said.

Twenty minutes later, a suicide bomber pushed his way into a crowd of police who had gathered at the site and detonated his explosives, killing Kizlyar’s police chief Vitaly Vedernikov and several other officers, authorities said.

After the blasts, two gutted cars stood near a deep crater on a debris-strewn street lined by bare trees. A red brick schoolhouse had its windows blown out and roof partly ripped off. A man’s severed head lay on the street.

Reports said there were no children in the school at the time of the blasts.

The two explosions killed 12 people, including nine police officers and a prosecutorial investigator, and 23 others were hospitalized, the federal Investigative Committee said.

He told a presidential Security Council meeting terrorists were trying “to sow fear and panic in the population. We will not allow this.” He said he had signed a decree aimed to improve security on public transport.