At least 21 people have been killed and more than 140 injured after three car bombs exploded today in volatile southern republics near Russia's rebel Chechnya province.
Officials quickly linked the bombings to Chechen guerrillas and President Vladimir Putin vowed to punish those responsible.
"The toughest measures will be undertaken to find and punish those who ordered and carried out these despicable murders," Putin said in a message of condolences to the relatives of the victims.
Nineteen died and more than 100 were injured when a car bomb ripped through a busy market in the resort town of Mineralnye Vody in the Stavropol region, Putin's envoy Viktor Kazantsev said.
Two police bomb experts died in the neighbouring republic of Karachayevo-Cherkessia while trying to remove an explosive device from the petrol tank of a car stopped at a police checkpoint.
Russian television said the car, whose driver has been detained, was apparently heading to the local capital of Cherkessk and suggested that the bomb was due to go off there.
Twelve other people were hurt, two seriously, when a third bomb exploded near a police station in the Stavropol town of Yessentuki shortly after the Mineralnye Vody blast.