By Missy Ryan and Alister Bull
BRASILIA/WASHINGTON (Reuters) - U.S. forces led the biggest military intervention in the Arab world since the invasion of Iraq on Saturday, but President Barack Obama insisted that U.S. involvement would be limited as part of an international effort to protect Libyan civilians.
The United States, France, Britain, Canada and Italy began attacks on targets designed to cripple Muammar Gaddafi's air defenses as the West tries to force the Libyan leader from power. At least some Arab nations are expected to join the coalition.
French planes fired the first shots, destroying tanks and armored vehicles in eastern Libya eight years to the day after U.S.-led forces headed across the Iraqi border in 2003. Hours later, U.S. and British ships and submarines launched more than 110 cruise missiles against air defenses in the oil-producing North African country.
The United States' huge military power dominated the initial phase of the strike and Army General Carter Ham, head of U.S. Africa Command, was leading the entire coalition. Pentagon officials said, however, their plan is take a smaller role over time in the operation, which was named Odyssey Dawn.
"Today I authorized the armed forces of the United States to begin a limited action in Libya in support of an international effort to protect Libyan civilians. That action has now begun," Obama told reporters in Brasilia, his first stop on a five-day tour of Latin America.
He said U.S. troops were acting in support of allies, who will lead the enforcement of a no-fly zone to stop Gaddafi's attacks on rebels.
"As I said yesterday, we will not, I repeat, we will not deploy any U.S. troops on the ground," Obama said, grim-faced as he delivered the news of U.S. military action in a third Muslim country within 10 years.
With the United States involved in long-running campaigns in Iraq and Afghanistan, Mark Quarterman, a senior adviser at the Center for Strategic and International Studies in Washington, said the war-weary American public was nervous about more military action.
"The way the U.S. has handled this -- the deliberations both in the Security Council and in Washington leading up to this -- has been calibrated to the concern that, yes, the U.S. is in two pretty serious wars now," Quarterman said. "The administration has made it very clear it has serious doubts about taking the lead in another military action in the Middle East."
Vice Admiral Bill Gortney, director of the U.S. military's Joint Staff, said of the U.S. role: "We are on the leading edge of a coalition military operation. This is just the first phase of what will likely be a multiphase operation."
25 COALITION SHIPS
The Obama administration had taken a lower profile in diplomacy leading to the U.N. resolution that set up the strikes, believing that it would allow Arab states to coalesce around a call for action and deny Gaddafi the chance to argue that the United States was again attacking Muslims.
"Even yesterday, the international community offered Muammar Gaddafi the opportunity to pursue an immediate ceasefire, one that stopped the violence against civilians and the advances of Gaddafi's forces," Obama said.
"But despite the hollow words of his government, he has ignored that opportunity," he said.
The Arab League, which had suspended Libya over its handling of the uprising, called for a no-fly zone on March 12, a key to securing U.S. and European backing.
Some 25 coalition ships, including three U.S. submarines and two guided-missile destroyers, are stationed in the Mediterranean. Five U.S. surveillance planes are in the area.
U.S. officials have said repeatedly it is time for Gaddafi to leave but have stressed that the goal of military action in Libya was different.
"It is to protect civilians and it is to provide access for humanitarian assistance," Secretary of State Hillary Clinton said in Paris, where she attended a conference called by French President Nicolas Sarkozy to discuss the international response to the Libya crisis.
A U.S. national security official following events closely said Gaddafi's air defenses had been severely disabled and that it was too early to predict what he might do in response to Saturday's strikes.
"After all, Gaddafi is one of the most unpredictable dictators on the planet and some of his loyalists can only be described as fanatical," the official said.