Authorities say a head-on collision between a streetcar and a trolleybus in the Czech Republic's second-largest city has injured up to 40 people.

Firefighters said the crash on a busy downtown street in Brno Monday afternoon injured passengers on the bus and the streetcar was empty except for the driver.

Rescue service spokeswoman Michaela Bothova said at least people suffered serious injuries.

The cause of the crash is under investigation.