At least 20 people were killed and more than 150 injured in Moscow on Tuesday morning during rush hour when a subway train derailed deep underground between subway stations. 

The exact cause of the crash is unknown, but officials have strongly denied any terrorism was involved.

“Around 100 ambulances are working at the incident site, four emergency helicopters are airlifting the injured people to hospitals," the health ministry said in a press statement, according to ITAR-TASS. The ministry said rescue work was continuing in the area.

Nearly 1,100 people were evacuated from the train, which crashed near the Park Pobedy subway station, the deepest station in Moscow, according to the Associated Press, complicating rescue operations.

More than 7 million people use the Moscow subway system, making it one of the busiest in the world, according to the Wall St. Journal

“It braked very hard," Reuters reported, citing a passenger who spoke with Rossiya-24, a local news network. The passenger added, "The lights went off and there was lots of smoke. We were trapped and only got out by some miracle. I thought it was the end. Many people were hurt, mostly in the first rail car because the cars ran into each other."


The Moscow mayor's office said the families of passengers killed  in the accident would receive of 1.5 million rubles ($43,652) in compensation, and those injured would receive 1 million rubles ($29,000).