A Hungarian woman has been killed and a South Korean woman seriously injured in a collision between two boats during a nighttime tourist trip to watch fireflies on a Thai river.

Police Lt. Col. Bhakin Sivamethakul says around 20 other people, mainly from South Korea, were also injured in the accident, which occured Friday night at Amphawa, a popular tourist destination about 60 kilometers (35 miles) west of Bangkok.

He says one boat, carrying 21 South Koreans and two Hungarians, was returning at the end of the trip when it was struck by an empty boat going in reverse.

Bhakin says the dead Hungarian tourist was hit on the head in the collision.

The drivers of both boats face the charge of causing death through negligence.