President Obama on Saturday strongly defended his decision to deploy the U.S. military to Libya, using his weekly radio address to offer perhaps his most detailed public explanation to date of his strategy in the North African country.

“I firmly believe that when innocent people are being brutalized, when someone like [Libyan leader Moammar] Gaddafi threatens a bloodbath that could destabilize an entire region, and when the international community is prepared to come together to save many thousands of live, then it’s in our national interest to act,” Obama said. “And it’s our responsibility. This is one of those times.”

The president has come under sharp criticism for not sufficiently explaining his strategy to Congress or to the broader public before committing U.S. forces to the Libya campaign.

He spent much of Friday after briefing members of Congress on his approach, and his aides announced Friday night that he would give a prime-time speech Monday, at the National Defense University in Washington, to detail his position before the American public.

“As I pledged at the outset, the role of American forces has been limited,” he said in Saturday’s address. “We are not putting any ground forces into Libya. Our military has provided unique capabilities at the beginning, but this is now a broad, international effort. Our allies and partners are enforcing the no-fly zone over Libya and the arms embargo at sea.”

He added, “This is how the international community should work, more nations, not just the United States, bearing the responsibility and cost of upholding peace and security.”