Oil and entertainment mogul Marvin Davis, attempting to take over Northwest Airlines, has promised to keep the carrier's headquarters in Minnesota, retain its managers and employees and expand its routes.

In a letter to Northwest's Board of Directors released today, Davis said his takeover "would be a positive step for the management and employees of the company, as well as for the citizens of the communities in which NWA operates, particularly the citizens of Minnesota."

The promises came one day after Minnesota Gov. Rudy Perpich pledged a united effort by state officials and union leaders to try to stop Davis from taking over NWA Inc., Northwest's parent company based in St. Paul.

The governor said a takeover by Davis, who has offered $2.6 billion, or $90 a share, for NWA Inc., might lead to the breakup of the airline and cost the state thousands of jobs and the airline's Twin Cities hub, devastating the state's economy.

In his letter, Davis said he was prepared to increase his offer in negotiations and also claimed that he could finance the acquisition without the sale of any of NWA's strategic assets.