Volkswagen CEO Martin Winterkorn speculated to the German press on Chinese interest in buying Opel.

GM has released a statement calling VW CEO's comments on a possible Opel sale "regrettable".

"In Wednesday's edition of the Frankfurter Allgemeine Zeitung, Volkswagen CEO Martin Winterkorn commented on rumors regarding Opel, which continues a regrettable pattern of fanning speculation as Opel makes solid progress in its restructuring, in generating improved operating results," said the GM statement.

Winterkorn speculated in an interview with the German newspaper that Chinese automakers would love to get their hands on Opel's technology and intellectual property as well as its assets in Europe such as its distribution network.

It is no secret that Chinese automakers have ambitions to sell cars in Western markets in the future, as do the Japanese and Korean automakers today.

Winterkorn also said it wouldn't be wise for GM to lose 5,000 engineers in a sale of Opel when engineers are in short supply in the industry.

GM is troubled by the loss-making Opel division but is too reliant on its technology for its global brands like Cadillac and Chevrolet to sell it off. GM says it is committed to turning the unit around.

"Opel has been part of the GM family since 1928 and remains important to the company. GM is pleased with Opel's solid progress over the last year in turning around its business, and the company continues to invest in outstanding products for the European market," GM said in a statement.

GM calls VW CEO's comments on possible Opel sale 'regrettable'