Russian investigators have arrested two subway employees in connection with a derailment that killed at least 21 people and wounded dozens. A faulty track switch is thought to have caused the accident.
Russia's federal Investigative Committee on Wednesday said it had detained a maintenance foreman and his assistant in connection with Tuesday's fatal accident on the Moscow subway, or metro.
"The detained have already been questioned," the committee said in a statement, saying that the arrests were connected to work on a new track switch mechanism carried out in May.
"The work was carried out improperly," the committee said. "This resulted in the train coming off the rails, the deaths of 21 people and various injuries to more than 150 passengers."
The train derailed during the morning rush hour between Park Podeby and Slavyansky Boulevard on the blue line in western Moscow. By the evening, President Vladimir Putin pledged a full investigation.
The Investigative Committee also indicated that more senior arrests could potentially follow, and that it intended to probe "absolutely everyone involved in this tragedy."
City authorities declared a day of mourning for the victims on Wednesday. Moscow's somewhat dilapidated subway system, in a city of more than 11 million people, is one of the world's busiest.
msh/mz (AFP, AP, Reuters)