The bombing by a U.S.-led international force started seven weeks ago. NATO took over command of aerial operations at the end of March.
Officials said NATO is working to disrupt Gadhafi's lines of communications with his troops.
Meanwhile, rebels said that forces loyal to Gadhafi have been shelling a road that is used to ferry supplies to rebel hideouts in western Libya. The road has been forced to close intermittently.
The Libyan leader has been fighting rebels in the east of his vast oil-rich nation since an uprising against his rule began in February.
Gadhafi's forces control most of western Libya except for a string of villages along the mountainous western border and the port city of Misrata.
The Associated Press contributed to this report.