Russian officials blamed both bombings on terrorists, and said the attacks are likely linked.
Vladimir Markin, the spokesman for Russia’s main investigative agency said Monday’s explosion involved a bomb similar to the one used in Sunday’s bombing at the city’s main railway station.
“That confirms the investigators’ version that the two terror attacks were linked,” Markin said in a statement. “They could have been prepared in one place.”
The blasts raise the specter of grisly terror attacks when the country hosts the upcoming Winter Olympics in less than six weeks.
No one immediately claimed responsibility for the bombings.
But they followed a recent call by rebel Chechen warlord Doku Umarov for “maximum force” against civilians in Russia, including at the Sochi Games scheduled to start Feb.
Russian President Vladimir Putin, who has vowed that the Games will be the “safest Olympics in history,” ordered law-enforcement agencies to beef up security at transit stations and airports
Officials reported the train-station bomber was a woman, but then said the attacker could have been a man.
The bomber detonated explosives in front of a metal detector just beyond the station’s main entrance when a police sergeant became suspicious and rushed forward to check ID, officials said. The officer was killed and several other policemen were hurt.
“When the suicide bomber saw a policeman near a metal detector, she became nervous and set off her explosive device,” Vladimir Markin, spokesman for the nation’s top investigative agency, said earlier in the day.