MOSCOW – A strong bomb shredded a passenger bus yesterday, killing eight people and injuring more than 60 in a central Russian city known for gang violence.

One official speculated the blast in Togliatti was a terrorist attack, but others said that was only one possibility.

They said investigators were also looking into whether it resulted from a turf battle between criminals or even the careless handling of explosives.

Police in the Volga River city also weren’t immediately sure whether the bomb was hidden inside or beneath the bus or carried on by a passenger, officials said.

With parliamentary elections coming up in December, the blast raised fears of another round of violence like that which has occurred before past elections.

“Due to [the blast’s] character, its consequences, the main version being considered is a terrorist attack,” Yuri Rozhin, head of a local branch of Russia’s Federal Security Service, the main KGB successor agency, said in a televised statement.

But President Vladimir Putin’s envoy to the Volga River region said other theories were also being considered.

“A terror attack is a likely theory, but not the main one,” envoy Alexander Konovalov was quoted as saying by the Interfax news agency.

Konovalov cited the possibility that someone may have been carelessly and dangerously carrying explosives, and he said investigators were also looking for links to gang rivalries in the city.

Togliatti is headquarters to Russia’s largest carmaker, AvtoVAZ, and the city has a reputation for gang violence as varying groups have competed for control of the lucrative state-owned factory.

The company could not say whether any factory workers were among the victims.

The green bus stood in the middle of the street, its windows blown out and roof partially peeled back, while paramedics attended to people with bloody faces and legs.

Valery Matkovsky, a local emergency official, said eight people died and 53 suffered burns and shrapnel wounds. Russian media said a child was among the dead, and Konovalov later raised the injury toll to 63.

The explosion, which broke windows in nearby apartment buildings, occurred near a bus stop in the city center during the morning rush hour. Some college students had left the bus at the stop just seconds before the blast, and about 20 of them were among the injured, NTV reported.

“If it had gone off just a minute earlier, it would have been much, much worse,” said Vadim Blagodarny, a 20-year-old photographer.