TOKYO - An express train and a truck collided in Japan's second-largest city of Yokohama on Thursday, train operator Keikyu Corp said, with fire officials confirming that about 30 people were injured.

The collision on a key rail link to Tokyo, the capital, smashed the glass in the driver's compartment and derailed at least the first 3 carriages of the 8-carriage train, video images showed, as rescuers surrounded the site.

"The sound of glass breaking was incredible," one passenger told national broadcaster NHK. "By the time I knew what had happened, the carriage was all smashed up."

The truck driver was severely hurt, but the injuries to the passengers and driver of the train did not immediately appear to be serious, NHK added.

Earlier, black smoke billowed from parts of the derailed train and the truck, which was crushed between the train and a wall, while smashed boxes and what appeared to be oranges littered the tracks.

Authorities, including the transport ministry, said they were investigating the cause but were unable to provide further details. Police confirmed a collision between a vehicle and the train, but could not elaborate, citing further investigations.

Images of people evacuating the train, a twisted electrical pole and train seats covered with broken glass figured in video posted on social media by shaken passengers.