At least 31 people were injured in a roller coaster accident at a theme park in southern Germany on Thursday. 

Two roller coaster carriages struck each other at Legoland, in the town of Günzberg, authorities said. At least one person was seriously injured, but did not have life-threatening injuries.

Police said adults and children were among those hurt on the "Fire Dragon" roller coaster.

Following the incident, authorities launched a large-scale rescue operation, including three helicopters. People had to be carried down from a height of at least five meters (16 feet), according to local reports. 

According to initial reports, one carriage stopped in an incorrect spot, and a second carriage ran into the back of it. Nobody fell out of the carriage, nor did the carriages derail.

The cause of the collision was unclear, but police are reviewing video recordings.

Park operators did not evacuate the park, and visitors reported no announcements being made to guests. The area was cordoned off, but the rest of the park continued to operate normally.

Journalists were blocked from the accident site, DPA news agency reported.

According to the park, the roller coaster travels at speeds of up to 29 kilometers per hour (18 miles per hour).

The park opened in 2002, and has 10 themed areas with more than 60 attractions and rides.

A woman died in a separate roller coaster accident last week in an amusement park in Klotten in southwest Germany. The 57-year-old woman fell out of the roller coaster as it was moving.

aw/wmr (dpa, Reuters, AP)