A new audio message from Gadhafi says his forces also are preparing for battle, and there is no way they will surrender.
The rebels have been hunting for Gadhafi since he was forced into hiding after they swept into Tripoli on Aug. 20 and gained control of most of the capital in days of fierce fighting.
Meantime, the U.N. humanitarian coordinator for Libya is warning that the country faces critical shortages of drinking water, food, fuel and medicine because of the civil war.
While fighting has subsided in much of Libya, including the capital, the six-month civil war disrupted supply lines and damaged infrastructure across the country.
The U.N. has brought in 11 million bottles of water and will bring in 600 tons of food and $140 million worth of medicine. But the help is expected to be temporary, officials said.
The Associated Press contributed to this report.