WASHINGTON - Operations to disarm Iraq have begun, President Bush announced during a speech to America tonight.

The president confirmed the early stages of military operations to disarm Iraq, to free its people and to defend the world.

News reports from Baghdad showed anti-aircraft artillery streaming into the sky. Western reporters spoke of hearing bombs drop in the western part of the city - which is home to many government buildings.

"On my orders, coalition forces have begun striking selected targets of military importance to undermine Saddam Hussein's ability to wage war," the president said from the Oval Office at 10:15 p.m. Eastern time. Bush stressed this will be a broad and concerted campaign.

He said the coalition - 35 nations contributing in a variety of ways - is moving to disarm Hussein and put a stop to his murderous rule. "Every nation in this coalition has chosen to bear the duty and share the honor of sharing in our common defense," Bush said.

Bush had direct words to the more than 250,000 U.S. service members in the area of operations. "The peace of a troubled world and the hopes of an oppressed people now depend on you," the president said. "That trust is well-placed. The enemies you confront will soon know your skill and bravery. The people you liberate will witness the honorable and decent spirit of the American military."

He said that once again Saddam Hussein has placed innocent civilians amid military targets. He assured the world that coalition forces will do all they can to minimize Iraqi casualties.

Bush observed the conflict will be dangerous, but U.S. commitment will not end with victory. He promised America will help feed the population of Iraq and rebuild the infrastructure of the oil-rich land.

But even then, the United States will not stay in the nation one second longer than necessary. "We have no ambition in Iraq except to remove a threat and restore control of that country to its own people," Bush said.

The president also spoke of the sacrifice made by the relatives of American service members. "I know that the families of our military are now praying that all those who serve will return safely and soon," he said.

"Millions of Americans are praying with you for the safety of your loved ones and for the protection of the innocent. For your sacrifice, you have the gratitude and respect of the American people. And you can know our forces will be coming home as soon as their work is done."

Bush pointed out that now is the time to confront the threat Saddam Hussein has become. Waiting will only make things worse, he said. "We will not live at the mercy of an outlaw regime that threatens the peace with weapons of mass murder. We will meet that threat now with our Army, Air Force, Navy, Coast Guard and Marines, so we will not have to meet it later with armies of firefighters, and police and doctors on the streets of our cities."

He stressed the U.S. military will apply decisive force to ensure a speedy campaign. "I assure you this will not be a campaign of half-measures and we will accept no outcome but victory," he said.