NATO agreed late Thursday, March 24, to take over part of the military operations against Libya - enforcement of the no-fly zone - after days of hard bargaining among its members. But the toughest and most controversial portion of the operation - attacks on the ground - will continue to be led by the U.S., which has been anxious to give up the lead role.

NATO Secretary-General Anders Fogh Rasmussen, who announced the agreement in Brussels, said the alliance could eventually take more responsibility, "but that decision has not been reached yet." It appeared that some NATO members balked at any involvement in attacks on ground targets, something the alliance's sole Muslim member, Turkey, has resisted.

In Washington, Secretary of State Hillary Clinton praised NATO for taking over the no-fly zone, even though the U.S. had hoped the alliance would take full control of the military operation authorized by the United Nations, including the protection of Libyan civilians and supporting humanitarian aid efforts on the ground. The operation cost the U.S. close to $1 billion in less than a week, and has drawn criticism in Congress from members of both parties.

NATO said that it expected to commence enforcement of the no-fly zone within two to three days. The operation will be commanded from Naples by Adm. Samuel J. Locklear, The Associated Press reported.