Libyan rebels say at least 23 people died in a rocket attack by Colonel Muammar Gaddafi’s forces on the western city of Misrata on Thursday.
A rebel spokesman said all of the victims were civilians and most of them were women and children.
Anti-Gaddafi forces have warned of a “massacre” if NATO does not step up its air strikes against the Libyan regime.
Misrata, the only rebel stronghold in western Libya, has been the scene of intense fighting as Gaddafi’s men battle to take back control of the city.
Eyewitness accounts from that part of the country are difficult to verify because foreign journalists are prevented from moving around freely.