Libyan military officials say pro-government forces have regained control of a border post in the western Wazin region, after rebels took over the crossing last week.
The French news agency (AFP) quotes witnesses who say some rebels fled into neighboring Tunisia on Thursday, as they were being chased by forces loyal to leader Moammar Gadhafi.
Meanwhile, pro-government forces and rebels are battling for control of the airport in the rebel-held city of Misrata.
Earlier, opposition sources said Gadhafi's forces had been firing rockets at Misrata and the western town of Zintan following NATO airstrikes to halt government attacks on Misrata's port.
On Wednesday, a NATO warplane mistakenly attacked a rebel position on the front lines in Misrata, killing 12 fighters and wounding several others.
A United Nations panel is pursuing an inquiry in Libya into violence and abuses committed during the government crackdown on the opposition.
A three-member commission sent by the U.N. Human Rights Council is seeking access to prisons and hospitals to interview possible victims of the crackdown.