Rebels in Libya's western mountains say they have advanced and are battling Muammar Gaddafi's forces in a strategic town south-west of the capital, ramping up pressure against government troops on a second front.
The rebels' claim of an advance into the outskirts of the town of Bair al-Ghanam, some 50 miles from Tripoli, follows weeks of intense fighting in the Nafusa mountains in which opposition forces have slowly pushed Gaddafi' troops back toward the capital.
Libya's rebels control the eastern third of the country and pockets, including a number of Nafusa mountain towns, in the west.
The bulk of the fighting in recent months has been focused on front lines to the east of Tripoli. But a push by rebels from the Nafusa mountains could force Gaddafi to commit more troops to the southern and western approaches to the capital.
A rebel military spokesman in the Nafusa mountains, Gomaa Ibrahim, said opposition fighters and government troops have been fighting since early on Sunday on the periphery of Bair al-Ghanam.
Guma el-Gamaty, a spokesman for the rebels' National Transitional council, said the town is significant because it is only 19 miles south of the city of Zawiya, a key western gateway to the capital and home to a crucial oil refinery.
Opposition fighters seized control of Zawiya in March before government troops crushed rebel forces there to retake the city. Fighting broke out in the city again earlier this month, briefly cutting access to the vital coastal highway that passes through Zawiya. The route links Tripoli with the Tunisian border and is one of Gaddafi's last main supply lines.
In Tripoli, Gaddafi's government remained defiant. Government spokesman Moussa Ibrahim said Gaddafi is in "high spirits" and remains in day-to-day control of the country. He insisted Gaddafi will remain in Libya, but would not confirm that the leader is still in the capital.
"Gaddafi is here, he is staying. He is leading the country. He will not leave. He will not step down," Ibrahim told reporters in Tripoli, challenging the rebels and the Nato-led coalition giving them air support. "If they want to continue the fight, we are ready. We will fight street to street, house to house."
As he spoke, deafening bursts of automatic rifle fire shot into the air by female soldiers and fresh civilian trainees rang out at a pro-government event in central Tripoli. Moussa told reporters that the government so far has distributed 1.2 million weapons to supporters in the west of the country to defend themselves.