"By 2:50 p.m. Moscow time [11:50 a.m. GMT], water in the Neva River rose 220 centimeters above the control mark," the service said. "We expect that the water will begin to recede some time soon."
Strong winds have contributed to the water rise, signaling the 302nd time the city has been flooded since it was established in 1703 by Emperor Peter the Great in the delta of the Neva River, which flows into the Gulf of Finland.
A storm warning has been announced in the city, which experienced its most devastating flood in 1824, when water rose to 421 centimeters above the control mark, killing some 200 people.
Basements and ground floors have been flooded in several buildings in the downtown area, including a medical center on the Fontanka embankment. The Fontanka, Karpovka and Angliiskaya embankments have all been flooded.
It is not clear whether metro stations near the river will be closed.
Flood conditions in the city are declared whenever the water level rises 160 centimeters above normal. A water rise of over 300 centimeters above the control mark is considered a disaster.
