The United States and its allies put up a united public front Thursday on the goals of NATO's stalemated military mission in Libya but failed to resolve behind-the-scenes bickering over how to achieve them.
NATO members agreed on paper with U.S. President Barack Obama that Moammar Gadhafi had to go to end the crisis, they also made clear that they would not be the ones to oust him. Although several NATO members want the alliance to commit more planes to expand the air campaign, a day of meetings in the German capital closed without any specific commitments for more aircraft.
U.S. Secretary of State Hillary Rodham Clinton appealed for unity, saying Gadhafi was taunting the alliance by continuing to strike cities held by rebels seeking his overthrow.
"As our mission continues, maintaining our resolve and unity only grows more important," Clinton said. "Gadhafi is testing our determination."
Late Thursday, Obama, British Prime Minister David Cameron and French President Nicolas Sarkozy said in a joint declaration that they will not stop the campaign and "remain united" in efforts to remove Gadhafi from power.
The statement, made available to The Associated Press in Paris, warned that unless Gadhafi leaves "definitively," his opponents faced vicious reprisals and the country could become a haven for extremists.
As attacks on opposition-held areas intensified in Libya, NATO foreign ministers met in Berlin to demonstrate commitment to a mission some nations have begun to second-guess. The United States is resisting suggestions that it resume a large combat role in Libya to help break a deadlock between rebels and better-armed forces loyal to Gadhafi.
Clinton and other top diplomats pointedly said their U.N. mandate for an air campaign does not extend to Gadhafi's exit by force.
The allies resolved anew to enforce a U.N. arms embargo, protect civilians acting to push Gadhafi forces out of cities they have entered, and get humanitarian aid in.
But differences over the scope of the military operation persisted, with Britain and France insisting on more action, particularly from sophisticated U.S. surveillance and weapons systems, and U.S officials maintaining that the alliance already has the tools to get the job done.
French Foreign Minister Alain Juppe said Paris "had wanted (NATO) to intensify its strikes, and we received the assurance that that would be the case."
Juppe, speaking after the day's sessions in the German capital, Juppe said NATO will appeal to members for more planes, but that it is too soon to predict which nations would step forward.
Juppe said he had spoken to Clinton, but he did not sound optimistic of a greater U.S. commitment.
"I think they will continue along the same lines," Juppe said of the United States, "which is to say punctual interventions when it is necessary and where the means they have are particularly useful."
Clinton did not say if the U.S. would send more ground attack craft, but she said Washington would continue to support the NATO mission until its goals were met.
The U.S. says it sees no need to change what it calls a supporting role in the campaign _ even though it has still been flying a third of the missions _ and many other NATO nations have rules preventing them from striking Gadhafi's forces except in self-defense.
The limitations of NATO's aims have been tested by the Libyan rebels' inability to make progress against Gadhafi's better organized forces. Government forces have camouflaged themselves and hidden in populated areas to avoid Western airstrikes that are now in their third week.
NATO Secretary-General Anders Fogh Rasmussen said NATO needed more aircraft to attack Gadhafi's forces in populated areas.
"To avoid civilian casualties we need very sophisticated equipment, so we need a few more precision fighter ground-attack aircraft for air-to-ground missions," he said. "I don't have specific pledges or promises from this meeting, but I heard indications that gave me hope."
In Washington, Marine Col. David Lapan, a Pentagon spokesman, said the U.S. has received no request by NATO to resume flying offensive strike missions.
Lapan said U.S. electronic warfare planes flew eight missions over Libya on Wednesday night and Thursday morning but fired no weapons. Those aircraft specialize in jamming or attacking radars and other elements of an air defense system. They are available for use in the NATO air campaign without advance approval from Washington because the Pentagon deems their missions to be defensive rather than offensive.
The Pentagon noted that Americans have flown 35 percent of all air missions over the last 10 days. Fogh Rasmussen said the alliance is keeping up "a high operational tempo."
Meanwhile, Gadhafi's troops unleashed heavy shelling for three hours on the besieged western port city of Misrata, which is partly held by rebels. At least 13 people were killed, underscoring the urgency of the situation. New explosions also rocked Tripoli, where anti-aircraft guns returned fire, apparently at NATO warplanes.
Ousting the longtime Libyan leader is not part of NATO's job, but Clinton called on nations around the world to "intensify our political, diplomatic and economic mission to pressure and isolate Gadhafi and bring about his departure."
In Cairo, U.N. Secretary-General Ban Ki-moon chaired a meeting of regional and international organizations on Libya and set three targets: reaching and implementing a cease-fire, delivering humanitarian aid and starting a dialogue on Libya's future.
France, which pushed NATO to launch the Libyan campaign, is now pushing other countries at the meeting to work "on more robust, more efficient, more rapid actions," French Foreign Ministry spokesman Bernard Valero said in Paris.
One proposal from Italy, Libya's former colonial ruler, calls for the western powers to provide defensive weapons to rebels. Clinton didn't comment on that plan but said the world must "deepen our engagement with and increase our support for" the Libyan opposition.
German Foreign Minister Guido Westerwelle said Berlin agrees with France and others that "Libya can only have a good future if this dictator goes."
In a related matter, the European Union rewarded the most senior official to defect from Gadhafi's regime by unfreezing his assets and lifting a visa ban that had barred him from traveling in any of the 27 EU countries.
The measure lifting sanctions against former Foreign Minister Moussa Koussa, which was agreed to Tuesday and made public Thursday, was at least in part an attempt to lure other senior figures into deserting Gadhafi defectors, an EU official said.
David Rising in Berlin, Angela Charlton in Paris, Don Melvin in Brussels and Robert Burns in Washington contributed to this report.