Libya's new rulers declared the country free from Moammar Gadhafi's 42 years rule Sunday as thousands gathered in Benghazi for the formal announcement of liberation.

In his speech, National Transitional Council Chairman Mustafa Abdel Jalil renewed an earlier promise to uphold Islamic law. He said Islamic Sharia law would be the basis of legislation in Libya.

This revolution was looked after by God to achieve victory, he said. All the martyrs, the civilians and the army had waited for this moment. But now they are in the best of places ... eternal heaven. 

U.S. President Barack Obama congratulated Libya on their declaration of liberation

After four decades of brutal dictatorship and eight months of deadly conflict, the Libyan people can now celebrate their freedom and the beginning of a new era of promise, Obama said in a statement. We look forward to working with the NTC and an empowered transitional government as they prepare for the country's first free and fair elections. 

Meanwhile, there is international disquiet about increasingly graphic and disturbing images of the abuse of a body that appears to be Gadhafi's following his capture and the fall of his hometown of Sirte Thursday. He died in chaotic circumstances after video footage showed him bloodied and struggling in the hands of his captors.

The Syrian-based Al-Rai TV station, which has served as a mouthpiece for the Gadhafi clan, said the dictator's wife, Safiya, also demanded an investigation.

I am proud of the bravery of my husband, Moammar Gadhafi, the holy warrior, and my sons who confronted the aggression of 40 countries over the past six months, the station her saying.