Published: Oct 04, 2010 7:53 PM EDT
Updated: Oct 04, 2010 4:53 PM EDT

WASHINGTON (AP) - The Justice Department on Monday sued credit card company American Express for alleged anticompetitive practices while proposing a settlement with the two biggest credit card companies, MasterCard and Visa.

In papers filed in federal court in Brooklyn, the department and various state attorneys general sued all three companies, saying they were attempting to insulate themselves from competition.

At the same time, the Justice Department filed a proposed settlement with Visa and MasterCard.

Attorney General Eric Holder planned an afternoon news conference on the issue.

The lawsuit says the card companies are impeding merchants from promoting the use of competing credit or charge cards with lower acceptance fees.

Each time consumers use a credit card to make a purchase, the merchant must pay a fee. Such fees brought in $35 billion last year to the three credit card companies and their affiliated banks.

Under the proposed settlement, Visa and MasterCard agree not to prohibit merchants from offering customers discounts or rebates for using a particular kind of card.