FRANKFURT (Reuters) -- Beijing Automotive Industry Holding Corp. (BAIC) has submitted an indicative, non-binding offer for General Motors' Opel, sources familiar with the situation said on Friday.

The Chinese automaker plans to make a binding offer by the middle of July, one of the sources added.

Magna International Inc., North America's largest auto-parts supplier, is the front-runner to take a majority stake in Opel and sister brand Vauxhall with a consortium including Russian state bank Sberbank and automaker GAZ.

But GM has said it is taking to other potential buyers for Opel including Belgium-based holding company RHJ International and BAIC, which builds Mercedes-Benz and Hyundai cars in China.

Analysts say BAIC is keen to expand out of its domestic market and build Opel into a global brand, but it has so far provided few details of its intentions. Its initial offer to investment bankers running the deal was just two pages long.

One source close to BAIC said it entered the bidding comparatively late because GM was reluctant to involve it in the process at all, as the U.S. carmaker does not want to create additional competition in China from Opel.

Magna ready to finalize deal

GM and the German government have piled pressure on Magna by talking up rival interest from Beijing Automotive and RHJ International in the run-up to July 15, when Magna wants to be able to sign a deal.

Analysts believe the only way Magna's acquisition of Opel would collapse is if Magna were to bow out of the talks, forcing GM to then negotiate with another bidder such as BAIC.

The Chinese carmaker is working together with advisers Deutsche Bank and PriceWaterhouseCoopers on the details of a bid it plans to submit by July 15 after examining Opel's data room last week, according to another source.

GM would likely retain the formal appearances of a bidding process by accepting further offers, only to then choose Magna as the winner.

In Moscow, Magna's Russian consortium partner Sberbank -- together they want to take a 55 percent stake in Opel -- said that BAIC, RHJ and Fiat are all effectively out of the race.

"I do not see any serious competition. The choice has been made and the question now is of how to structure the deal," CEO German Gref told reporters.

Reuters reported on Thursday that the board of directors of Magna is due to approve its plan for the acquisition of Opel on Tuesday.

Two sources familiar with the matter told Reuters the Canadian auto parts supplier and GM had already clarified most of the major issues in weeks of tough negotiations and they expect to resolve the last few issues holding up the takeover by July 7.