US role in Libya's conflict will be limited.

Nato forces led by the US, France and Britain began air attacks on Libyan government troops on 19 March in order to enforce a United-Nations-sanctioned no-fly zone and protect civilians.

In a televised address on Monday, Mr Obama said it was in the country's national interest for the US to be involved in the fighting and that military actions have stopped Libyan leader Muammar Gaddafi's troops from advancing.

He stressed, however, that though American forces had led the initial air strikes, they would now hand over to NATO allies, which took full command of the military operation this week.

Mr Obama said the US has helped to prevent a massacre in Libya and would continue to work with other nations until Colonel Gaddafi relinquished power.

"We will deny the regime arms, cut off its supply of cash, assist the opposition and work with other nations to hasten the day when Gaddafi leaves power," he said.

He warned, however, that trying to oust Col Gaddafi by force could repeat the carnage of Iraq.

Meanwhile, Russia has renewed its expressions of concern, saying intervention in what it calls an internal civil war is not sanctioned by UN Security Council resolution 1973.