A second bomb exploded in the town of Buinaksk in the North Caucasus republic of Dagestan on the way of police officers heading to the site of the first blast, a Dagestani police source said.
"According to preliminary data, the explosive device was planted at the roadside. It went off after the car with police officers passed by, so no one was killed or injured," the source said.
An investigation is underway.
Earlier on Sunday, three people died and 26 were injured in an attack on a military unit in Buinaksk when a car, most likely driven by a suicide bomber, exploded.
MAKHACHKALA, September 5 (RIA Novosti)
