Combat units cross into Iraq amid efforts to persuade Iraqi forces to give up

American and British combat units rumbled across the desert into Iraq on Thursday and bombed limited targets in Baghdad. But military commanders withheld the massive onslaught that would signal all-out war as U.S. officials tried to talk the Iraqi regime into giving up.

Coalition forces suffered their first casualties in a helicopter crash that left 12 Britons and four Americans dead.

"The days of the Saddam Hussein regime are numbered," Defense Secretary Donald H. Rumsfeld predicted, although he also said there was "no need for a broader conflict" if Iraqi leaders surrender.

On the second day of Operation Iraqi Freedom, American officials held out the tantalizing possibility that Saddam had been killed in the initial Wednesday night bombing of Baghdad.

State-run Iraqi television said Saddam survived, and met with his top aides to counter the U.S.-led attack. "We are resolved to teach the criminal invaders hard lessons and make them taste painful punishment," declared the Iraqi military.

Intelligence analysts tried to determine whether a man in military garb shown on state-run television was the Iraqi leader or a double. U.S. intelligence believes Saddam and possibly two of his sons were present inside a suburban Baghdad compound when it was struck and that medical attention was summoned afterward. There was no definitive word whether Saddam was caught in the pre-dawn attack.

The onset of war sparked anti-war demonstrations across the country -- more than 1,000 were arrested in San Francisco -- and at U.S. embassies around the world. The State Department warned U.S. citizens abroad of an increased danger of terrorism.

Rumsfeld hinted that talks with Iraqi military elements, including some in the elite Republican Guard, may have been behind a delayed start to a planned massive aerial assault.

"We still hope" the Iraqi leadership can be replaced "without the full force and fury of a war," Rumsfeld said after meeting with lawmakers on Capitol Hill.

Rep. Robert Andrews, D-N.J., said following a House briefing with Rumsfeld that "the behavior of those who've not surrendered would suggest that they might."

In southern Iraq, white light glowed in the desert sky, and the sound of explosions could be heard from across the Kuwait-Iraq frontier as the 3rd Infantry Division unleashed an artillery barrage. Troops eager to cross the border into Iraq cheered -- and units were soon on their way.

The 101st Airborne Division rumbled across the desert in a vast convoy -- trucks, tankers, Humvees and more rolling along under a round white moon.

Iraq sent missiles toward Kuwait in retaliation for the pre-dawn attack against Saddam, and American officials said the Iraqis had set fire to some of their own oil wells. Protecting the oil-rich Basra region was one of the American military's goals as Marines and Army special forces headed into Iraq.

The Iraqi missiles landed harmlessly in the Kuwaiti desert. Officials said none of the Iraqi missiles caused injuries, and one was intercepted by a Patriot missile. Thousands of American and British troops donned protective gear, but there was no evidence the missiles carried chemical or biological weapons.

Prime Minister Tony Blair, Bush's staunchest ally in the war effort, went on television to tell his country that British forces were "engaged from air, land and sea. Their mission: to remove Saddam Hussein from power and disarm Iraq of its weapons of mass destruction," he said in the recorded address.

It was the second straight night that cruise missiles and bombs penetrated Baghdad.

This time, officials said the targets included facilities of the Special Republican Guard and the Special Security Organization. The organization, run by Saddam's younger son, Qusai, oversees most security and intelligence activities in Iraq.

Red and white anti-aircraft tracers lit the night sky and a huge plume of smoke rose from the west bank of the Tigris River in central Baghdad.

A senior defense official with direct knowledge of the operation said about two dozen Tomahawk missiles were fired from two American and two British submarines, plus one American surface ship. The vessels were in the Persian Gulf and the Red Sea.

But two officials, speaking on condition of anonymity, said the night strikes were not the beginning of the massive air assault that Pentagon officials have said they plan to unleash.

In Washington, the Senate unanimously approved a resolution supporting U.S. military forces, while protesters briefly blocked one of the Potomac River bridges carrying traffic into the capital. Outside the White House, demonstrators shouted, "No blood for oil."

In an unusual diplomatic move, the Bush administration called for the expulsion of Iraqi diplomats by all countries that recognize and deal with the government in Baghdad.

State Department spokesman Richard Boucher said the diplomats represented a "corrupt and ruthless regime."

The Bush administration seized $1.75 billion in Iraqi assets already frozen in the Gulf War, saying the money would be used for humanitarian purposes in Iraq.

A U.S. humanitarian effort already is beginning. Agriculture Secretary Ann Veneman said the United States is sending 200,000 tons of wheat and rice to Iraq. "President Bush has assured the people of Iraq that they will have the food and medicine they need," she said.

Bush, who spent a full day, starting at 7 a.m., dealing with the war, planned to leave the White House early Friday afternoon for his customary weekend at Camp David.