Washington D.C. saw its deadliest crash ever after two subway trains collided during rush hour on Monday.

At least four people, one of which is a female train operator, were killed and 70 injured, ABC reported.

We are extremely saddened that there are fatalities as a result of this accident, which has touched our Metro family. We hope to have more details about the casualties later today. Our safety officials are investigating, and will continue to investigate until we determine why this happened and what must be done to ensure it never happens again, Metro General Manager John Catoe said.

In January 1982 was the only other time in Metrorail's 33-year history that there were customer fatalities.