The White House on Friday sent condolences to Russia after the derailment of an express train running from Moscow to St. Petersburg, which killed at least 23 people and injured dozens of others.

White House spokesman Robert Gibbs said in a statement that the United States is "deeply saddened by the terrible loss of life and injuries."

"Our hearts go out to the families of those who lost loved ones, and we wish a speedy recovery to the injured," he said.

Russian authorities said four carriages of the train went off the tracks at 9:30 p.m. Moscow time (1830 GMT) near the town of Bologoye on the border between Tver and Novgorod regions.

The reason behind the incident was not immediately clear, but the state-run railway company said the derailment could have been caused by an act of terrorism.