(Recasts to add comment from a Lufthansa spokesman)

ROME/FRANKFURT, Oct 10 (Reuters) - German carrier Lufthansa has written to Italy's industry ministry and Italian railways Ferrovie dello Stato to say it is still interested in struggling airline Alitalia, an Italian source said on Wednesday.

Ferrovie dello Stato, U.S. airline Delta and infrastructure group Atlantia have been discussing how to revive Alitalia for months, pushing back various previous deadlines for making a firm proposal.

A binding offer is due to be presented by Oct. 15, but sources have told Reuters there is still no final accord on a bid among prospective investors.

A spokesman for the German carrier declined to comment on Lufthansa's letter and reiterated the airline had always said that the Italian market was important.

The spokesman also said the carrier would be interested in Alitalia only once restructured, adding Lufthansa could imagine a commercial partnership with the Italian airline. (Reporting by Stefano Bernabei in Rome and Hans Seidenstuecker in Frankfurt; Editing by Nick Macfie )