VALLETTA, Malta — An open-top double-decker tourist bus slammed into a low-hanging tree branch in Malta on Monday, killing two people and injuring 50 others, including a dozen children.

The accident happened in Zurrieq, a popular tourist destination just outside the capital that is famous for its ruins and “blue grotto.”

Police said the two passengers who died were a 37-year-old Spanish woman and a 62-year-old Belgian man. They and most of the people injured were sitting on the top deck when the bus hit the branch.

Health Minister Chris Fearne said most of the passengers hailed from Belgium or Britain, though police said the seriously injured also included a German and an Italian.

Twelve of the 50 people hurt were children, two of whom suffered critical injuries.

The 24-year-old bus driver was not hurt.

Hop-on, hop-off buses are common for sightseeing in major cities in the United States and Europe.

In November 2015, 19 people were injured when a double-decker tour bus in San Francisco crashed into pedestrians, vehicles and construction scaffolding.

San Francisco police concluded the driver of the open-top bus had been going too fast.