China's Beijing Auto said intellectual property issues were behind its failure to reach a deal to buy General Motors' Opel-Vauxhall unit.

GM has agreed to continue detailed talks with both Magna and RHJ International but has seemingly discounted Beijing Auto, which had also submitted an offer.

The Chinese company said in a statement: ""In the negotiations over intellectual property, we have been in constant communications with [General Motors]. Regrettably, both parties failed to reach agreement on [the intellectual property] issue."

But it gave no details on what these issues were. Beijing Auto had pledged to maintain GM's stake in Opel to the largest extent, to ensure Opel's market share in Europe remained stable and to support the brand's expansion into the Chinese market.

Beijing Auto did not say if it would pursue its interest in Opel but sources told Reuters this week that the Beijing city government would fully support a bid by the company for Ford's Volvo car unit if the company failed in its quest for Opel.

The carmaker is controlled by the Beijing government and aims to more than double its annual vehicle sales to 2million units by the end of 2015 from 771,639 units last year.

Reuters noted that the company, ranked fifth in China, does not even have its own car brand. Its four year old Mercedes-Benz car venture with Daimler broke even last year and its tie-up with Hyundai Motor has a long way to go before catching up with top players in the market such as Volkswagen.