Suspected armed robbers raided one of Europe's biggest art fairs in the Dutch city of Maastricht in broad daylight on Tuesday, police said, with video showing men smashing a display case with a sledgehammer.

"Police are investigating a possible armed robbery of the TEFAF in Maastricht. Four suspects are believed to be involved. They are now searched for by multiple units," Limburg province police said on Twitter.

The European Fine Art Fair, commonly known as TEFAF, is one of the biggest in Europe and regularly draws tens of thousands of visitors.

© Agence France-Presse