Russian investigators say they have detained two metro workers over a devastating crash in the Moscow subway that killed 22 people, as anger mounted over the tragedy.

City authorities declared a day of mourning on Wednesday, after the worst accident in the metro’s eight-decade history, while Muscovites swapped stories of how the authorities had ignored their complaints about the overcrowded system.

• Subway accident kills scores

“Nightmare in the Metro,” declared mass-circulation daily Moskovsky Komsomolets, while business daily Vedomosti ran with “Deepest Tragedy”.

Disaster struck on Tuesday when a trail braked sharply and three carriages derailed between the recently built Park Pobedy station, the deepest in the ornate marble-clad system, and Slavyansky Boulevard in western Moscow.

The health ministry said 22 people have now died and that of 150 people hospitalised, several dozen were in a serious condition.

Teams worked around the clock to clear away the debris, while investigators said they had arrested two metro workers for alleged safety breaches.

A special investigative committee, which reports directly to President Vladimir Putin, said it was holding maintenance foreman Valery Bashkatov and his assistant Yury Gordov.

“The detained men have already been questioned,” the committee said, adding that they would soon be formally charged with safety breaches.

Putin swiftly ordered a criminal probe.

The committee said work had been under way at the spot since May to install a set of points, a section of track allowing trains to change lines, which had been overseen by the suspects.

“A set of points was fixed in place with a piece of ordinary three-millimetre wire which snapped,” it says, adding that higher-ranking officials could also be held responsible, as it intended to probe “absolutely everyone involved in this tragedy”.

Deputy mayor Maxim Liksutov insisted there were no problems prior to the crash, pointing to stringent safety requirements on the system, one of the busiest in the world with nearly nine million travellers per day.

But reports that the authorities repeatedly dismissed complaints about the Park Pobedy-Slavyansky Boulevard stretch have gone viral on social networks.