WASHINGTON– American and British forces unleashed a punishing air attack Sunday against military targets and Osama bin Laden’s training camps inside Afghanistan, striking at terrorists blamed for the attacks that murdered thousands in New York and Washington.

“We will not waver, we will not tire,” said President Bush, speaking from the White House as Tomahawk cruise missiles and bombs found targets halfway around the globe. “We will not falter and we will not fail.”

Under a campaign dubbed “Enduring Freedom,” the assault was accompanied by airdrops of thousands of vitamin-enriched food rations for needy civilians — and by a ground-based attack by Afghan opposition forces against the ruling Taliban.

In a chilling threat, bin Laden vowed defiantly that Americans “will never dream of security or see it before we live it and see it in Palestine, and not before the infidels’ armies leave the land of Muhammad.” He spoke in a videotaped statement prepared before the attacks, but both he and the leader of the Taliban ruling council of Afghanistan were reported to have survived the initial action.

In a fresh reminder of the potential for renewed terrorist attacks, the FBI said it was urging law enforcement agencies nationwide to “be at the highest level of vigilance and be prepared to respond to any act of terrorism or violence.”

Bush ordered the strike on Saturday, less than four weeks after terrorists flew two hijacked airplanes into the World Trade Center twin towers and a third into the Pentagon. A fourth plane crashed in the Pennsylvania countryside after an apparent struggle between passengers and terrorists on board.

Besides the Sept. 11 death toll — estimated at more than 5,000 — the attacks dealt a shuddering blow to Americans’ feeling of security, and propelled an already weakened economy toward recession.

“I know many Americans feel fear today,” Bush said in his nationally televised announcement from the White House Treaty Room. Signs of heightened security concerns were evident, as officials took Vice President Dick Cheney from his residence to an undisclosed secure location, security was stepped up around the Capitol and government nuclear weapons labs were put on higher alert. The FBI said it was acting on the basis of “the possibility of additional terrorist activity occurring somewhere in the world.”

Within hours of the attacks, Bush drew public support from foreign leaders around the world, as well as from congressional leaders and the American public.

A crowd of 64,000 cheered the president’s words at Veterans Stadium in Philadelphia, where the beginning of a professional football game was delayed so the fans could view Bush’s appearance on the big screen scoreboard. Chants of “USA, USA” filled another stadium, this one in Atlanta.

The initial strike involved 50 Tomahawk cruise missiles, launched from American and British ships. Gen. Richard Myers said 15 bombers and 25 strike aircraft, both sea and land-based, also were involved. The assault came at 12:30 p.m. EDT — nighttime in Afghanistan.

Myers, sworn into office as chairman of the Joint Chiefs of Staff less than a week ago, said the attacks included B-1, B-2 and B-52 bombers as well as ships and submarines that have been deployed in the region in the days since Sept. 11.

The B-52s dropped at least dozens of 500-pound gravity bombs on al-Qaida terrorist training camps in eastern Afghanistan, one official said.

Defense Secretary Donald H. Rumsfeld said the strikes were designed to eliminate the Taliban’s air defenses and destroy their military aircraft. Afghanistan’s rulers are known to have a small inventory of surface-to-air missiles as well as shoulder-fired anti-aircraft missiles.

Afghan sources in Pakistan said the attack had damaged the Taliban military headquarters and destroyed a radar installation and control tower at the airport in the southern Afghan city of Kandahar.

Roughly an hour after the first volley of cruise missiles, Taliban forces came under attack from the northern alliance, Afghan opposition forces who fired multiple-rocket launchers from an air base about 25 miles north of Kabul.

A spokesman at the Afghan Embassy in Tajikistan, a nation that does not recognize the Taliban as rulers of Afghanistan, said that the opposition could make an attempt to enter Kabul, the capital. Asked when, he said perhaps in days or a week.

Bush spoke less than an hour after the first explosion could be heard in Kabul, followed by the sounds of anti-aircraft fire. Power went off throughout the city almost immediately after the first of five thunderous blasts.

The president said the military strike would be accompanied by the delivery of food, medicine and other supplies needed to sustain the people of Afghanistan. “This food is a gift from the United States of America,” says the inscription, in English.

Bush said the military effort was only part of a campaign against terrorism, “another front in a war that has already been joined through diplomacy, intelligence, the freezing of financial assets and arrests of known terrorists by law enforcement agents in 38 countries.”

He said Canada, Australia, Germany and France have “pledged forces as the operation unfolds,” and numerous other countries have granted air transit or landing rights. Still more nations are providing intelligence, he said.

To help sustain the coalition, officials said Bush was sending Secretary of State Colin Powell to Pakistan and India in the next few days. Pakistan has emerged as a key ally in the war on terrorism. India, in turn, has expressed concern lest the United States begin to favor Pakistan in a long-term struggle over the disputed territory of Kashmir.

British Prime Minister Tony Blair offered strong support in a speech to his own nation. He said of the Taliban, “They were given the choice of siding with justice or siding with terror. They chose to side with terror.”

German Chancellor Gerhard Schroeder also expressed his support, and the Russian foreign ministry said all means must be used to fight terrorism. Russian President Vladimir Putin has become an important supporter of the U.S.-led campaign against terrorism, opening Russia’s airspace to U.S. deliveries of humanitarian aid and encouraging former Soviet republics in Central Asia to lend their backing.