The strikes were designed to counter an assault by the dictator whose soldiers carried out sustained shelling and artillery attacks over the weekend. Coalition aircraft targeted Gaddafi troops outside Ajdabiya, in eastern Libya and Misurata, the only rebel held town in the west, which has been under siege for six weeks.
The strikes came as a delegation of African leaders arrived in Tripoli to try and persuade Gaddafi to halt the violence being meted on his own people.
Jacob Zuma of South Africa and Denis Sassou Nguesso of Congo were among those who flew to the capital and plan to go on to the rebel stronghold of Benghazi.
Nato's air attacks, combined with rebel fighting, brought to a halt the advances of Gaddafi's troops, who were believed to have killed at least 30 rebels in Misurata.
