Frankfurt - Fiat chief executive Sergio Marchionne met Monday with General Motors Europe (GME) executives west of Frankfurt as two rival bids for the maker of Opel and Vauxhall cars awaited a decision.

Both Fiat and Magna, a Canadian-based parts maker, have drafted bids for the European factories of troubled US maker General Motors.

Berlin has demanded that both specify by Wednesday how much they would invest.

Opel sources said Marchionne met at Ruesselsheim, where the main Opel factory is located, with Carl-Peter Forster, head of GME, and Hans Demant, head of its Adam Opel unit, for two hours.

German trade unions have been hostile to the Fiat bid, which foresees the closure of an Opel engine plant.

German Economics Minister Karl-Theodor zu Guttenberg said in Munich he was waiting to see the proposals on Wednesday.

He said this might prompt a German government delegation to visit Washington at the weekend, adding he would leave it open whether he would take part in the trip. The administration of US President Barack Obama is overseeing efforts to rescue GM by cutting costs.

Berlin has been rebuffed by Washington in a request that GM surrender its European interests to a trust so they cannot be seized by creditors. (dpa)