The European Commission has raided some of Europe's biggest producers and importers of sinks, taps and other bathroom fittings, seeking evidence of a suspected cartel, the EU's executive said.

The Commission said the raids, carried out with national authorities, had spanned five countries. Germany's Grohe and Hansgrohe both confirmed they had been part of the investigation.

"On November 9 and 10, Commission inspectors... launched simultaneous unannounced inspections at the premises of some of the major European manufacturers and importers of bathroom fittings in Austria, Belgium, Germany, Italy and the Netherlands," the Commission said in a statement.

Europe's largest fittings manufacturer Grohe, which is owned by buyout firms Texas Pacific Group and Credit Suisse First Boston Private Equity, said it had been raided.

A spokesman for Grohe Water Technology in Hemer said the company was raided by German and EU officials.

"These investigations have obviously taken place in the whole sanitary industry," he said. "We assume that the findings will prove groundless."

Rival Hansgrohe, majority owned by the US Masco Corp., said it too had been raided. "We are cooperating completely with the EU authorities," a spokesman said.

Dutch newspaper NRC Handelsblatt reported the Dutch Foundation for Heating & Bathroom Fixtures was also raided, but the trade group could not be reached for comment.

The Commission did not identify any of the firms concerned but said most operated on a European level.

"The manufacturers are suspected of having exchanged information on price increases before their implementation, on rebates and discounts and other sensitive business information such as individual sales data," the Commission said.