NEW YORK (AP) _ American Express launched a broadside at Visa, suing its rival in the credit card wars to force the withdrawal of an advertisement proclaiming that the Telluride, Colo. ski resort only accepts Visa cards.

''We are doing this because we believe the Visa ad is lying,'' said Mike O'Neill, a senior vice president at American Express.

The suit, filed Tuesday in federal court in New York, says the Visa television ad implies that all the resort town's businesses refuse to accept the American Express card.

In fact, the only institution that dropped the card was Telluride Ski Area Inc., operator of the resort's ski concession, American Express says.

In addition, the suit says the ad doesn't mention that Telluride Ski Area Inc. only dropped American Express because Visa promised it millions of dollars in free promotions to do so.

Telluride Ski Area spokesman Mike Shim-Konis said the commercial is intended to focus only on the ski resort, not the town.

Shim-Konis added that Visa ''didn't offer us millions of dollars.''

''It was mutually agreed upon that they would provide us exposure and they would have the opportunity to affiliate themselves with an up-and-coming ski resort,'' he said.

David Brancoli, a spokesman for Visa U.S.A. Inc, said the company stood behind its ad.

''It's passed the highest standards of all the networks,'' he said. He acknowledged that Visa provided free advertising to some merchants who refused to accept the American Express card.

American Express is seeking a temporary restraining order against the advertisement. It wants to follow that with a permanent ban, and is asking unspecified damages.

Visa and American Express, the two best known credit cards, have been targeting each other in aggressive advertising and promotions.

Last month, American Express ran a two-page ad in the New York Times accusing Visa of ''seducing'' merchants by offering free promotions if they rejected the American Express card.

O'Neill said American Express also has some exclusive arrangements with merchants, but added: ''We do not use those for competitive advantage purposes.''

Visa started running ads featuring merchants that accepted Visa cards and not American Express in 1985.