A national advertising regulatory group on Monday scolded U.S. Bank over claims the Minneapolis bank made in promoting its FlexPerks Visa travel rewards credit card. U.S. Bank said the ads no longer are running and it would take the nonbinding decision under advisement.

The claims were challenged by American Express Co., which is offering a competing card tied to Delta Air Lines' SkyMiles frequent-flier program.

Both cards have been fighting for the hearts and wallets of former users of U.S. Bank's Northwest Airlines WorldPerks Visa card.

The National Advertising Division (NAD) of the Council of Better Business Bureaus -- an investigative arm of the advertising industry's voluntary self-regulation program -- recommended that U.S. Bank stop making the following claims: that FlexPerks offers "more value" for building up airline travel, that earning rewards is "slow" with SkyMiles but "fast" with FlexPerks, and that SkyMiles redemptions are subject to "blackout" dates and "capacity controls."

In addition, the agency said FlexPerks advertising should disclose that its claim that the SkyMiles card can be used in "half as many places" as the FlexPerks card is based on global data, not domestic.

NAD did, however, say that the FlexPerks program did support its "Free vs. Fee" claim," saying that Delta's passenger fees are a "real and significant" difference between the SkyMiles program and the U.S. Bank FlexPerks program.

U.S. Bank spokesman Steve Dale said the disputed ad campaign was an old one that's no longer being used. "It boils down to two sides agree to disagree," he said. "We're glad to consider [NAD's] comments, and we appreciate their efforts."

NAD can only make recommendations, but its decisions do carry some weight. Companies that don't abide by the terms of NAD decisions or don't participate in proceedings may have their advertising referred to the Federal Trade Commission, said Linda Bean, NAD director of communications.

Suzanne Ziegler • 612-673-1707