Police in the German city of Braunschweig cancelled a popular Carnival street parade on Sunday because of fears of an imminent Islamist terror attack.

Police spokesman Thomas Geese said police received credible information that there was a "concrete threat of an attack with an Islamist background" on Sunday's parade and therefore called on all visitors to stay at home.

"Together with city officials and organizers we evaluated the information and then, at very short notice, decided to cancel the street parade," Geese told The Associated Press.

Geese said the parade was canceled less than 90 minutes before its scheduled start and that "many people arriving at the train station from out of town were already dressed up and very disappointed -- but we didn't want to take any risks."

Braunschweig's Carnival parade is the biggest one in northern Germany and draws around 250,000 visitors each year.

Geese denied to give further details regarding the nature of the threat, but did say that the warning came from intelligence sources.

The city's mayor, Ulrich Markurth, said the cancellation marked a "sad day for our city ... and a sad day for our democratic society."

Organizers and city officials announced that the many marching bands, which had planned to participate in the parade, would instead play their music at the city's town hall in the afternoon.

Braunschweig's police chief Michael Pientka told German public radio NDR that there was no connection to the terror attacks in Copenhagen, Denmark, where an attacker killed two men this weekend, one at a free speech event and the other at a synagogue.

Carnival is celebrated in many regions of Germany with parades, music, revelers dressing up in costumes and dancing in the streets.