* Cartel office says carried out searches in flat steel
* Salzgitter, ArcelorMittal say units were searched
* Thyssenkrupp, Kloeckner say were not searched (Adds ArcelorMittal, German steel federation)
FRANKFURT/DUESSELDORF, Sept 4 (Reuters) - Germany’s competition regulator said on Monday it has widened an investigation into a suspected violation of antitrust laws in the steel industry, with ArcelorMittal and Salzgitter confirming searches at some of their units.
The investigation expands an ongoing cartel office inquiry, which already covers makers and sellers of stainless steel, car manufacturers and suppliers as well as companies in the forging sector.
“I can confirm that the cartel office has carried out searches in the area of flat steel on Aug. 22, 23 and 24 at seven companies as well as three private homes,” a spokesman for the cartel office said, confirming reports by monthly Manager Magazin and daily newspaper Rheinische Post.
“There is suspicion of anticompetitive collusion between the companies,” he added.
ArcelorMittal, the world’s largest steel producer, said searches had taken place on its premises in Germany, adding it was fully cooperating with the authorities.
Salzgitter, Germany’s second-largest steelmaker, said several of its units had been searched on Aug. 22 on suspected violation of antitrust rules.
Larger peer Thyssenkrupp and steel distributor trader Kloeckner & Co both said they had not been searched.
Manager Magazin said, without citing any sources, that the most recent investigation also included the German Steel Federation, an industry association. A spokesman for the federation declined to comment. (Reporting by Christoph Steitz and Anneli Palmen; Editing by Maria Sheahan and Andrew Heavens)