U.S. Secretary of State Hillary Clinton said on Thursday that establishing a no-fly zone over Libya would require the bombing of air defenses, as the U.S. seeks broad action to protect civilians fighting Libyan leader Muammar Gaddafi's regime.

A no-fly zone requires certain actions taken to protect the planes and the pilots, including bombing targets like the Libyan defense systems, she said in Tunisia on Thursday on the last day of a weeklong trip to Europe and the Middle East which has seen a strong focus on the Libyan crisis.

The comments come as international representatives at the United Nations consider a new round of resolutions to take action against the regime of Libyan leader Muammar Gaddafi, whose forces are engaged in armed conflict with rebels for control of the country.

Susan Rice, the U.S. Ambassador to the United Nations said on Wednesday that the U.S. supported a no-fly zone over Libya and also saw the need for broader action to protect civilians engaged in battles with Libyan leader Muammar Gadaffi.

The United States, which had previously said it was considering a no-fly zone as a possibility, has now followed France and Britain in pushing for establishing it.

We are interested in a broad range of actions that will effectively protect civilians and increase the pressure on the Gadhafi regime to halt the killing and to allow the Libyan people to express themselves in their aspirations for the future freely and peacefully, she told reporters at the United Nations in New York.

Rice made the comments after eight hours of talks. Over the past week, Secretary of State Hillary Clinton has traveled to Paris to meet with European leaders on the next steps for addressing the unrest in Libya which has evolved into armed conflict between pro and anti-Gaddafi groups.

President Barack Obama and his administration have urged Gaddafi to leave the country and have previously said all options were being considered in how to deal with the crisis.

Rice left open the possibility for additional measures.

Those include discussion of a no-fly zone, but the U.S. view is that ... a no-fly zone has inherent limitations in terms of protection of civilians at immediate risk, she said.

Top U.S. military officials have previously testified before Congress that establishing a no fly zone over Libya would first require bombings.