Struggling Prime Retail Inc., one of the nation's largest factory outlet shopping center owners, said yesterday that it has agreed to sell two centers in Colorado for $96 million to an undisclosed buyer.

The Baltimore-based company, which has sold several centers over the past year to trim its huge debt, said it will use proceeds from the sale of the two Colorado properties to make payments on a mortgage loan with a $338.9 million balance and a shorter-term, high-interest "mezzanine" loan with a $31.1 million balance.

The company is required to make a $12 million payment on the mezzanine loan by the end of the year, said Robert A. Brvenik, Prime's president and chief financial officer. Brvenik declined to say how much Prime would pay on its larger mortgage loan.

Prime, which owns and manages 40 centers, including three in Maryland, said in a statement yesterday that it expects the sale to close in this quarter.

The properties sold include its outlet center in Castle Rock, Colo., a 478,000-square-foot center built 10 years ago, according to Prime's Web site. The other property, an 8-year-old, 328,358- square-foot center, is in Loveland.

Prime previously had announced that it is selling its newest outlet center - a 176,000-square-foot mall that opened in July 2000 - in Barceloneta, Puerto Rico, for $36.5 million. That sale also is to an unspecified buyer and is expected to close during the fourth quarter.

Shares of Prime, which trade on the over-the-counter market, remained unchanged yesterday at 9 cents.