Allied warplanes have launched further air strikes on Muammar Gaddafi’s forces for a fourth day, notably in western Libya.
The coalition has confirmed artillery and tanks besieging the rebel-held town of Misrata were targeted.
Despite some condemnation of the West’s intervention, military chiefs have defended their role.
Senior US military chief officer Peg Klein said: “Some of those cities still have tanks advancing on them to attack the Libyan people. We are authorised, and the President made the nexus between the Security Council resolution and what he considers our legal mandate to attack those tanks. And so that is the type of target that our strike aircraft will go after.”
Many of the American air strikes are being launched from ships in the Mediterranean.
Despite that, Washington has made it clear it wants to take a back seat in the military mission and is calling on other members of the coalition to take operational command.