Forces loyal to Libyan leader Moammar Gadhafi are pounding targets in the western rebel stronghold of Misrata.
Medical authorities and rebels say the shelling on Friday had killed at least 10 people and left 40 wounded.
The attack by pro-Gadhafi forces come as NATO warplanes continue strikes over the capital, Tripoli.
The forces appear to be targeting several parts of the capital, but it was not immediately clear what was hit or whether there are casualties.
NATO has most often struck under the cover of darkness, but day-time assaults have become more common. Friday's raids followed a barrage on Thursday night.
Meanwhile, Libyan state television showed what it said was live video on Friday of a pro-Gadhafi rally in a Tripoli square. The video showed what appeared to be hundreds of people waving flags and chanting pro-government slogans.
Elsewhere, there are tentative attempts to resolve Libya's three-month-old political conflict.
Gadhafi's son said his father was willing to hold elections and step aside if he lost. But the offer was rejected by rebels and the United States.
Seif al-Islam Gadhafi told an Italian newspaper, Corriere della Sera, Thursday the vote could take place within three months and transparency could be guaranteed by international observers.
Opposition spokesman Abdel Hafiz Ghoga told al-Jazeera television the time for elections had passed "because our forces are at the outskirts of Tripoli." A U.S. State Department official also dismissed the idea.
Italy said it will host a meeting of up to 300 Libyan tribal leaders to help promote reconciliation.
Some information for this report provided by AP, AFP and Reuters.