SANTIAGO, Chile (AP) — At least two people were killed and nine others injured Thursday when a train full of passengers collided head-on with another train on a test run just outside Chile's capital of Santiago.

Investigations were underway to determine the cause of the crash, which vaulted one car fully on top of a car from the other train.

The eight-car freight train, which was carrying 1,346 tons of copper, was also packed with people, while the other train had 10 workers on board operating a speed test, the state rail company said.

Authorities have not identified the two people killed. The nine injured included four Chinese nationals who were receiving treatment at hospitals near the crash site in San Bernardo, Chile.

“We have to identify what the causes are and take the corresponding measures,” Transportation Minister Juan Carlos Muñoz told The Associated Press.