Berlin/Vienna  - General Motors (GM) is to hold fresh top- level talks in the US with Opel-bidders Magna later Thursday, sources close to the negotiations have confirmed.

The talks at GM's Detroit headquarters are to include GM head Fritz Henderson and Magna's co-chief executive Siegfried Wolf, as well as the head of Russian state-owned Sberbank, German Gref, sources told German Press Agency dpa - confirming a previous report by German daily Bild.

Sberbank, whose backing of car-parts supplier Magna's bid has been viewed critically in Detroit, is participating for the first time at the negotiations.

The purpose of the meeting is to iron out final issues, said a source familiar with the negotiations.

However, Thursday's talks did not imply that Magna was now in a favoured position, as it was unclear whether a similar meeting was also taking place with rival bidders, RHJ International, the source added.

German unions, and the governments of all four German states where Opel has factories, have endorsed Magna's bid, after Germany pledged 1.5 billion euros (2.13 billion dollars) to keep Opel afloat.

GM, on the other hand, has praised RHJ's offer as being simpler to implement. It also leaves open the possibility of a future Opel buyback for GM.

The GM management board is expected to meet late Thursday or Friday, when it could issue its recommendations on the sale of Opel, according to information from the German finance ministry. GM would not confirm the meeting.

The final word in the drawn-out negotiations rests with the trust into which Opel has been placed - which includes the German federal government and regional German states in which Opel has factories, as well as GM.

The German state and regional governments have said that neither Magna nor RHJ's bid would bring enough capital into the deal.

However, both bidders have shown that they are flexible on this issue. (dpa)