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 25 cents, or more than 18 percent, to $1.13 in Monday afternoon trading, mirroring a decline in the broader market.

Chicago-based General Growth Properties, which owns Ala Moana Center and several other shopping malls in Hawai'i, 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.

Shares of General Growth fell 29 cents to close at $1.09 today on the New York Stock Exchange.