At least six people have been killed after a car drove into a crowd of carnival-goers in southern Belgium.
The incident happened in the small town of Strépy-Bracquegnies, about 30 miles (50km) south of the capital Brussels.
The car drove at high-speed into dozens of people who were preparing to take part in a traditional parade on Sunday morning.
Around 40 people were injured and several are in a serious condition, the town's mayor said.
"There were about 150-200 people who were following the parade and [the] car arrived from behind and drove into the crowd," Jacques Gobert said.
"It continued for another 100m (328ft)," he added. "It should be considered a national catastrophe."
The exact circumstances of the attack are being investigated, but police said a terror attack had been ruled out.
"It is an accident, a tragic one. The car hit the group and tried to carry on but it was quickly stopped by the police," police spokeswoman Cristina Ianoco told the BBC.
"The driver and the other people in the car have been detained," she added. They have not been identified.
Police denied earlier reports in some Belgian media that the crash, which happened at around 05:00 local time (04:00 GMT), followed a high-speed police chase.
"Deepest condolences to the families and friends of those killed and injured in the incident this morning," Belgian Interior Minister Annelies Verlinden wrote on Twitter.
"What was supposed to be a great party turned into a tragedy," she added.
Prime Minister Alexander De Croo, who is expected to visit the scene later on Sunday, said it was "horrible news".
"A community gathering to celebrate has been hit in the heart," he said.
Belgian towns and villages host traditional street carnivals around the period of Lent. The event in Strépy-Bracquegnies, like many others, features a parade with participants dressed up comical figures.