The government of the state of Mexico and the suburban train company on Sunday began investigating the cause of Saturday night's crash, which injured some 130 people.

Rescue workers survey the scene after a train collision in Tlanepantla, Mexico, Saturday, April 18, 2009. [Xinhua]

Train operator Ferrocarriles Suburbanos said it had begun an investigation and expressed sympathy for the passengers who were affected.

The accident occurred when a train crashed into another that had been halted for unknown reasons in the town of Tlalnepantla in Mexico state, the administrative region immediately surrounding Mexico City.

Rescue workers attend to an injured passenger after a train collision in Tlanepantla De Baez April 18, 2009. [Xinhua]

On Sunday, 109 injured people were released from hospital, but officials said another 20 or more remain in hospital.

(Xinhua News Agency April 20, 2009)