At least 30 people were injured when a car crashed into a lenten parade in a German town on Monday, with the driver arrested at the scene.

A silver BMW estate car mounted the kerb and crashed into a Rose Monday parade in the town of Volkmarsen on Monday afternoon, with dozens — including children — injured. While there is no official indication yet of why the driver may have done this, a police spokesman reported by local newspaper Frankfurter Rundschau states the act was deliberate, but stopping short of calling it an attack.

“Due to the situation… an attack cannot currently be ruled out”, police said. British newspaper the Daily Telegraph cites German sources that claimed the driver deliberately served around barriers set up around the carnival.

There were no deaths reported from the scene but the number of injured reported quickly rose from a dozen to more than 30. Dozens of ambulances and a police helicopter attended the scene.

A 29-year-old man, reported to live locally and driving a car with locally issued licence plates, was arrested at the scene.

Rose Monday or Rosenmontag is the height of the traditional German carnival season, taking place annually on Shrove Monday before lent begins on Ash Wednesday. It is marked across Germany with costumed parades with impressive floats. Some of the grotesque carnival creations are so ornate, photographs are often reported in newspapers worldwide, and particularly from the city of Cologne where the tradition of highly provocative, controversial floats is perhaps strongest.

Other cities and towns cancelled their parades Monday as a security measure.

Anticipating a potential terror attack against the Cologne carnival, the organisers set out a total ban against large trucks and lorries in the city centre for the duration of the event in 2017, shortly after a Christmas market in Berlin was driven into by an Islamist extremist in a hijacked heavy vehicle.