NATO has underestimated the ability of Muammar Gaddafi's regime to offer resistance to rebel forces assisted by NATO-led air campaign, French Foreign Minister Alain Juppe said.
An international military operation "to protect civilians" in Libya began on March 19 following a UN resolution and has been extended until September.
"We have probably underestimated Gaddafi's forces' resistance, but we are not bogged down," Juppe said on Thursday in an interview broadcast by France 2 television.
The French minister said the coalition will continue to exercise military pressure on Gaddafi's regime.
The uprising which began in mid-February in Libya against Gaddafi's forty-year rule has already claimed thousands of lives, with Gaddafi's troops maintaining their combat capabilities despite NATO airstrikes against them.
France has played a key role in NATO's four-month campaign in Libya.