A series of bomb explosions shook a regional capital in southern Russia on Monday, killing at least three people and wounding more than 20, officials said.

The explosions occurred near two cafes (searchand a bus stop in Krasnodar, about 750 miles south of Moscow (search), said Vitaly Tushev, a duty officer at the local branch of the Russian Emergency Situations Ministry.

Tushev said that the type of the explosives and possible motives behind the blasts weren't immediately known. Some officials pointed to terrorism, while others suggested that a criminal score-setting might have been the aim.

Another regional ministry official, Alexander Lemeshev, said one victim was killed instantly, and two others later died of wounds in the hospital. He said that 23 people were injured, with 18 of those hospitalized. Earlier, officials had given a lower number of injured.

Lemeshev said the bombs were stuffed with metal bolts, nuts and screws for maximum damage.

He said the attacks appeared to be linked to a property dispute between two local criminal clans. Other officials also pointed at a link to the criminal underworld. However, they also said investigators weren't excluding a terror attack.

Local police chief, Sergei Kucheruk, said the fact that the explosions occurred virtually simultaneously in crowded public places backed the theory of a terror attack.

Russia has been rocked by bomb explosions recently and other attacks which the government usually has blamed on the Chechen rebels.