Top-level talks between the German government, the U.S. and investors to save General Motors Corp.'s (GM) Adam Opel GmbH from insolvency will only take place if potential investors and GM agree on relevant points and if "substantial" plans, such as a letter of intent, are provided, the German government said Friday.

As a result, it's yet unclear whether Friday's meeting between the government, the U.S. and investors to rescue General Motors Corp.'s (GM) Adam Opel GmbH would take place, government spokesman Thomas Steg said told reporters

By Andrea Thomas, Dow Jones Newswires; +49 (0)30-2888 410; andrea.thomas@dowjones.com