The bus following the rout Slavic Boulevard -Skolkovo belonging to Mostransavto transportation service drove into the underground passage next to 2, Slavic Boulevard building in Moscow.
A bus has driven into a pedestrian underpass in the center of Moscow, killing at least 5 and injuring 15 others, a source in the emergency services told Sputnik.
It was not immediately clear what caused the accident as authorities said they were looking into several possibilities, including a technical malfunction.
"Nine people are now in the city's clinics. four people died on the spot", the Moscow city hall said in a statement on the website. The driver of the bus was taken into custody.
"The driver has been detained".
Three people have been hospitalised, the statement added.
Another angle shows the bus seemingly stationary on the side of a snowy road before it appears to pull away in the direction of the metro station.
The accident occurred in a busy area near the Slavyansky Bulvar metro station when a large number of people were in the underpass.
Sobyanin has vowed to conduct a "thorough" probe into the deadly accident.
Russian news agencies quoted Moscow mayor Sergei Sobyanin as saying that he had ordered all city buses to be checked in the aftermath of the crash.