BERLIN (AFP)--Germany's foreign affairs minister appealed for international help for struggling General Motors Corp.'s (GM) European unit Opel in remarks published Saturday amid reports the car maker may go under without public aid.

"We have to look further than our own backyard. No car factory is capable of surviving alone in Germany or elsewhere," Foreign Minister Frank-Walter Steinmeier told the daily Rheinische Post.

"We must act on an international and European level to preserve jobs in a sustainable manner in Russelsheim, Kaiserslautern, Bochum and Eisenach," he said, listing Opel's main factories in Germany.

Steinmeier's remarks coincided with a report in the Bild newspaper that Opel may go bankrupt by May or June if public assistance is not forthcoming.

Other reports said Friday the German car maker needs more than 3.3 billion euros ($4.2 billion) in public loan guarantees - nearly double the figure previously expected.

Opel has neither confirmed nor denied these figures, while suggesting nonetheless that it needed more aid.

Like its rivals, Opel has been slammed by slumping auto sales, especially in Europe.

Directors of Opel's troubled U.S. parent company General Motors opened the door this week to an Opel spin-off within the framework of a broad restructuring of GM's whole business.

Earlier this week, GM said it planned to cut 47,000 jobs worldwide, close plants, kill off brands, slash production and revamp its product offerings in order to return to "sustainable profitability in 24 months."

The largest U.S. auto maker said it could require a further $16.6 billion in U.S. government loans by 2011 in addition to $13.4 billion approved in December.

The plan also depends upon receiving $6 billion in funding support from the governments of Canada, Germany, the United Kingdom, Sweden, and Thailand "to provide liquidity specifically for GM's operations in these countries," it said.