WASHINGTON — Shopping-mall owner General Growth Properties Inc. is getting a two-week extension on $900 million in debt that had been scheduled to come due last week as the company works to stave off bankruptcy and negotiate longer-term extensions with lenders.

The mortgages cover two malls, Fashion Show and Palazzo, in Las Vegas, the company said late Sunday. Shares fell 24 cents, or more than 17 percent, to $1.14 yesterday, mirroring a decline in the broader market.

Chicago-based General Growth Properties, whose Hawai'i holdings include Ala Moana Center and Ward Centers, has been hit hard by the deteriorating U.S. economy and problems at struggling U.S. retailers. Analysts are unsure whether new managers, installed in late October, will be able to keep the company afloat given its staggering debt load.

"It will be incredibly difficult for General Growth to deal with the mountain of obligations that are coming due next year," said Benjamin Yang, an analyst at research firm Green Street Advisors, in an e-mail.

General Growth's struggles come amid concern about commercial real estate debt. Industrywide about $20 billion will be due next year, covering everything from office and condo complexes to hotels and malls.

The retail outlook is particularly bad. Circuit City Stores Inc. and Linens 'n Things have sought bankruptcy protection. Home Depot, Sears, Ann Taylor and Foot Locker are closing stores.

"Many of these loans will become a nightmare as a severely slowing economy, significantly tighter credit requirements and falling commercial real estate property prices force many borrowers to default over the coming years," JPMorgan Chase & Co. analyst Alan Todd wrote in a research note last week.

General Growth said in a Securities and Exchange Commission filing last month that it faces nearly $3.1 billion in maturing debt next year, and warned that inability to refinance that debt "raises substantial doubts as to our ability to continue as a going concern."