The Moscow police department corrected its earlier report, which had said the cash was from a branch of Sberbank located next to the bookshop. The shop said 600,000 rubles of its funds had been stolen.
A police department source said: "The men who were robbed were hired privately by the shop's management to transport cash. Three unidentified individuals, threatening them with pistols, took their bags with the money and fled."
The incident is the latest in a wave of armed robberies in Russia.
Late on Saturday night armed robbers broke into a bank in West Siberia, killing a security guard and making off with more than $600,000. In a similar attack on a branch of state-run savings bank Sberbank in the East Siberian city of Chita on May 12, robbers killed two security guards and stole more than $1.5 million in cash, along with gold and silver bullion.
On April 1, robbers unsuccessfully attempted to raid a courier van in Moscow.