FRANKFURT (Reuters) - German carmaker BMW (BMW.DE) faces a fine of at least $100 million euros in India for alleged violations of import rules, WirtschaftsWoche reported.

India's customs office claims that BMW has for years declared imported car parts as part of larger assemblies rather than as separates, paying lower import duties than it should have as a result, the German weekly magazine said.

Customs authorities have imposed a fine of at least $100 million, which could grow further in a second stage, WirtschaftsWoche said, without specifying where it obtained the information.

It said BMW has appealed the decision.

A spokesman for the carmaker said an investigation was ongoing and the company was cooperating with Indian authorities. He declined to comment on the status of the probe.

Indian customs authorities were not immediately available for comment on Saturday.

(Reporting by Christoph Steitz; Additional reporting by Krishna N Das in New Delhi; Editing by John Stonestreet)