"Couriers delivering cash to a bank [TransCreditBank] came under armed attack at around 10:00 a.m. local time (5:00 a.m. GMT) on Monday," the source said.

The victims have been hospitalized with gunshot wounds, the spokesman said, adding that "An unidentified attacker fled the crime scene."

Investigators are currently trying to locate the robber.

TransCreditBank [RTS: TKBK], set up in November 1992 as the bank of the state-owned Russian Railways monopoly, is ranked by the Central Bank among the nation's top 30 banks in terms of assets.