© RIA Novosti/NewsTeam/Abdula Magomedov
Four police officers have been killed and five others were injured when a vehicle exploded at a road police post in Russia's Republic of Dagestan. The explosion happened during a routine road inspection.

The initial blast killed three policemen, while the fourth died from his injuries in a hospital hours later. One person remains unaccounted for. The body of the suicide bomber was so badly damaged by the explosion that "nothing's left of him," a source told Interfax news agency.

Police estimated the yield of the explosive device to be about 100 kilograms of TNT. The blast left a crater 1.5 meters deep and 4 meters in diameter, and badly damaged a checkpoint building.

Hours after the explosion, local security forces spotted a gang of militants that may have been connected to the suicide bombing. The gang was cornered near a local village.

Six militants were eliminated following the attack, RIA Novosti reported.

"There is information that they may have been involved in an attack near a police post earlier today," the news agency said, citing the police press office.
Police also discovered a hidden cache in which explosives may have been prepared before being loaded into the car.

The explosion occurred near the entrance to the city of Khasavyurt, Dagestan, early in the morning as police ordered the driver of a Lada Priora to stop his car for an ID check.

By intercepting the explosives-carrying vehicle at a checkpoint outside the city center, law enforcement officers prevented an attack in a more densely populated area, Dagestani security officials said.

The Russian Interior Ministry has dispatched a team of investigators to help Dagestan probe the bombing.