Forces loyal to Libyan leader Moamer Gaddafi launched another attack against rebels in the western cities on Saturday, the rebels said, dpa reported.
One of the rebels told broadcaster Al Jazeera broadcaster that Gaddafi's forces shelled the city of Zintan with over 40 Grad rockets. The number of causalities remains unclear.
Government forces on Saturday also launched a new operation against Zawiya city from the east using a large number of tanks, opposition activists said.
The shelling comes after clashes near the rebel-held city of Misurata that killed more than 30 people on Friday.
Protests against Gaddafi, who has been in power for 42 years, began in mid-February, but soon turned into an armed conflict following a lethal government crackdown on demonstrators.
Gaddafi's forces have been trying to enter the city and stop the rebels in Misurata from advancing on the town of Zlitan.
Fierce clashes have been going on in Zlitan for days, activists said online.
Shelling by government forces on Kekklah town, in the western Nafusa Mountain area, resulted in the destruction of al-Manarah mosque which was recently built.
Opposition groups reported online that Gadaffi forces that defeated in the nearby al-Galaa town, joined with those attacking Kekklah.
The clashes come after Turkish Prime Minister Recep Tayyip Erdogan said his country can help Gaddafi find a new place to live as he "has no choice" but to leave Libya.
Erdogan's offer, to organize Gaddafi's departure and relocate to a place of his choosing, came after a letter - purported to be from Gaddafi - suggesting to the US Congress that he is ready to negotiate a ceasefire in the three-month-old conflict.
Congressional officials said they were examining the authenticity of the letter, according to ABC News and Politico newspaper.
Gaddafi proposed a ceasefire in April, however, opposition forces said they would not accept any deal unless Gaddafi leaves the country.