U.S. and European diplomats moved quickly Monday to rally wavering Arab support for military intervention in Libya after key Arab officials complained that Western airstrikes appeared to exceed the narrow mandate authorized by the United Nations.

The diplomatic outreach came as the first Arab warplanes to participate in the enforcement of the U.N.-backed no-fly zone — up to six French-built Mirage 2000 fighters from Qatar — began making their way toward Libya. Qatar is the only Arab country so far to firmly commit to contributing military firepower to the enforcement effort.

The Obama administration had stressed that Arab support was a precondition for foreign military action in Libya, but apparent waffling by some Arab leaders since the start of the bombing Saturday has raised concerns in Washington and other capitals. Secretary of State Hillary Rodham Clinton joined British and French counterparts over the past two days in phoning Arab leaders to shore up support after Libyan officials asserted that Western airstrikes had killed dozens of civilians.

British Foreign Secretary William Hague said Monday that he had spoken with Arab League Secretary General Amr Moussa and other Middle East leaders and was convinced that support for the no-fly zone remained firm.

“I did not detect in them any weakening of their commitment,” Hague said in a BBC Radio interview.

The concerns stemmed partly from statements made Sunday by Moussa, who said he was calling an emergency meeting of the Arab League after news reports from Libya showed Western warplanes and missiles striking dozens of targets, including antiaircraft batteries and tank columns. “What has happened in Libya differs from the goal of imposing a no-fly zone, and what we want is the protection of civilians and not bombing other civilians,” he said.

But less than 24 hours later, Moussa appeared to have shifted course, telling reporters that Arab League members “respect the U.N. resolution, and there is no conflict with it.” The head of the organization’s Paris mission, Nassif Hitti, issued an even stronger endorsement, saying it was an “Arab and nationalist duty” to defend Libyan civilians from attack by their country’s strongman leader, Moammar Gaddafi.

“The Libyan situation is very dangerous. There are fears over the future of Libya,” Hitti told reporters at a conference in Abu Dhabi, the United Arab Emirates.

Despite the apparent stiffening of resolve, Arab states have been slow to offer material support for the Libya mission. Obama administration officials said last week that they were hoping that at least two Persian Gulf countries would agree to send aircraft to help enforce the no-fly zone. But Monday, the United Arab Emirates, which has several squadrons of U.S.-made F-16 fighters, announced that it was contributing only humanitarian relief. Jordan also has pledged humanitarian assistance, while Tunisia and Egypt are helping support large numbers of refugees spilling across the border to escape the fighting in Libya.

During a news briefing Monday, State Department spokesman Mark Toner acknowledged that Qatar alone had committed military assets to the enforcement effort, but he insisted that “we believe we’ve got Arab support.”

“We need to let this process play out,” Toner said. “We’re at a stage now where obviously — as we were quite clear — the U.S. and other key allies had certain assets brought to bear. This is going to be an operation moving forward.”

The 22-member Arab League strongly condemned Gaddafi’s assaults on Libyan civilians in its March 12 resolution calling for an international enforcement of a no-fly zone. It was the first time the league had called for military action against one of its members, and that resolution became the basis for the U.N. Security Council resolution last Thursday that authorized the use of force against Gaddafi.

Yet, it remains politically difficult for many Arab states to use force against another Muslim country or to publicly side with Western powers in an attack on another Arab leader — even one as unpopular in the Arab world as Gaddafi, said Clifford May, president of the Foundation for Defense of Democracies, a Washington think tank.

“On the one hand, they find Gaddafi a menace and an embarrassment,” May said, “and on the other hand, some are afraid that the same arguments being used to take down Gaddafi could be used against their own regimes.”

Staff writer Karen DeYoung contributed to this report.