"We struck regime forces approaching Benghazi to save that city and the people within it. We hit Qaddafi's troops in neighboring Ajdabiya, allowing the opposition to drive them out. We hit Qaddafi's air defenses, which paved the way for a no-fly zone. We targeted tanks and military assets that had been choking off towns and cities, and we cut off much of their source of supply," Obama said.   

U.S. President Barack Obama speaks about Libya at the National Defense University in Washington, Monday, March 28, 2011. [Xinhua]

But he reiterated that "America's role would be limited" and vowed that the U.S. would not put ground troops into Libya.

NATO has taken command of the enforcement of the arms embargo and the no-fly zone, said Obama, adding that the transfer will take place on Wednesday.

Obama also said that United States will continue to play a "supporting role" -- including intelligence, logistical support, search and rescue assistance, and capabilities to jam regime communications.

The transition to a broader, NATO-based coalition will help to significantly reduce the risk and cost of the operation to U.S. military and American taxpayers, explained Obama.

"Qaddafi has not yet stepped down from power, and until he does, Libya will remain dangerous," Obama said, arguing that "history is not on Qaddafi's side."  

He expressed his confidence that the coalition will keep the pressure on Qaddafi's remaining forces.