Cairo, Egypt (CNN) -- The United States and its allies should recognize and arm a provisional government in Libya and also impose a no-fly zone that would prevent Libyan aircraft from attacking anti-government protesters there, two leading U.S. senators said Sunday.
Sens. John McCain, R-Arizona, and Joseph Lieberman, an independent from Connecticut who caucuses with the Democrats, told CNN's "State of the Union" that the Obama administration needs to do more to help protesters oust Libyan leader Moammar Gadhafi.
"I think the world has to do more," Lieberman said. "I'd begin with the imposition of a no-fly zone, so that Gadhafi can't be attacking his own people from the air."
In addition, Lieberman said, "We've got to recognize the opposition provisional government as the legitimate government of Libya and that we ought to give that government certainly humanitarian assistance and military arms, not to go in on the ground ourselves, but give them the wherewithal to fight on behalf of the people of Libya against a really cruel dictator."
Both Lieberman and McCain stopped short of calling for U.S. forces to get involved. McCain added that the United States and allies should make clear that any foreign mercenaries backing Gadhafi in attacking the Libyan people would face a war crimes tribunal.
Both senators, speaking from Cairo, Egypt, said they understood the administration's concern over making statements or taking steps that could endanger American citizens in Libya, but they called the response so far insufficient.
"Get tough," McCain said. "I understand that the security and safety of American citizens is our highest priority. It's not our only priority."
People throughout the Middle East and around the world were " looking to America for leadership, for assistance, for moral support and ratification of the sacrifices they've made in the defense of democracy," McCain said. "America should lead."
Libya descended further into chaos Sunday, with Gadhafi, the nation's leader for more than 40 years, clinging to power in Tripoli after weeks of protests.
On Saturday, President Obama said Gadhafi "has lost the legitimacy to rule and needs to do what is right for his country by leaving now." Secretary of State Hillary Clinton also issued a statement urging the Libyan leader to step down.
In addition, both the United Nations Security Council and the United States are imposing new sanctions that target the Libyan leadership.
Lieberman, who chairs the Senate Committee on Homeland Security and Governmental Affairs, said he understood the administration's initial hesitation in speaking out on the crisis in Libya, but added that a strong message was necessary.
"Frankly I wish we had spoken out much more clearly and early against the Gadhafi regime," Lieberman said, adding "the fact is, now is the time for action, not just statements."
Saying he hoped that new sanctions would be successful, Lieberman added that the United States should be ready to do more.
"I hope that the opposition forces may end all of this by ... taking it all over and ending the Gadhafi regime, but if they don't, we should help them," Lieberman said.
McCain, meanwhile, predicted the end of Gadhafi's rule, with the only question being how many people get killed until that happens.
CNN's Gabriella Schwarz and Tom Cohen contributed to this report