Air France-KLM could provide strategic or financial help in Delta Air Lines' pursuit of a merger with another airline, a newspaper reported on Thursday.

A US congressman on Wednesday said Delta has begun merger talks with Northwest Airlines, and media reports have said it was also talking to United Airlines parent UAL.

The Wall Street Journal report, quoting people familiar with negotiations, said Northwest was more likely to emerge as Delta's "preferred partner" and that Air France-KLM may back up that bid.

Air France-KLM could provide cash, sweetening a deal and making a rival bid more difficult, while seeking a stake in the combined carrier in return, the report said.

Air France-KLM already cooperates with Delta and Northwest as part of the SkyTeam global alliance. Analysts have also said a Delta-Northwest tie-up was more likely, some noting Delta Chief Executive Richard Anderson's past leadership at Northwest.

Air France declined to comment on the report. Delta was not immediately available for comment.