U.S. led forces are liberating Baghdad and removing the Saddam Hussein regime "from its seat of power," Defense Secretary Donald H. Rumsfeld declared Wednesday.

"Saddam Hussein is now taking his rightful place alongside Hitler, Stalin, Lenin, Ceausescu in the pantheon of failed brutal dictators and the Iraqi people are well on their way to freedom," Rumsfeld told a Pentagon briefing.

"This is a very good day," Rumsfeld said as U.S. forces stormed through the streets of the Iraqi capital and were greeted by jubilant Baghdad residents.

Rumsfeld called such images, broadcast around the world, "breathtaking."

Rumsfeld and Air Force Gen. Richard Myers, chairman of the Joint Chiefs of Staff, cautioned that despite the day's developments, there still remained much work to be done and some hard fighting might lay ahead.

"Other Iraqi cities are still being contested," even though the capital was not, Rumsfeld said.

He said that U.S.-led forces still needed to find the seven American prisoners of war who were captured by Iraqi troops, and to locate the regime's weapons of mass destruction.

Rumsfeld encouraged Iraqi scientists, military officers and others to come forward with information, saying "rewards are available to those who help us."

Myers said there were still Iraqi death squads operating west of Baghdad and pockets of resistance to the north.

"We must not and should not become overconfident," Myers said.

Myers said there were more than 10 regular Iraqi army divisions intact in the north and one brigade of the Republican Guard.

The Pentagon officials shed no new light on Saddam's personal status after Monday's U.S. bombing in a residential area of the capital that had targeted him and his sons.

Rumsfeld answered "don't know" to questions about whether Saddam was dead or alive, or if he was in the bombed building.

"He's either dead, or he's incapacitated. Or he's healthy and cowering in some tunnel someplace trying to avoid being caught," Rumsfeld said.

"He's not been around, he's not been active," Rumsfeld noted.

He said it was hard to find a single person. "It is hard to find them when they're alive and mobile, it's hard to find them when they're not well and it's hard to find them if they're buried under rubble."

Of the broader war effort, "There's a lot of work left to do," the defense secretary said.

However, he said the country was "tipping," meaning it had reached the point where Iraqi citizens were shedding their fear of Saddam and his government and were becoming more accepting of the presence of U.S.-led coalition forces in their country.

Rumsfeld also had stern words for Syria, reiterating earlier assertions that the government was serving as a conduit for military equipment, including night-vision goggles, heading to Iraqi forces.

"They would be well advised not to provide military equipment to Iraq," he said. "I find it notably unhelpful."

Rumsfeld also suggested that the Syrian government was helping Saddam loyalists to leave Iraq and cross the border into Syria.

Asked if any other countries beyond Iraq were potential targets for use of U.S. military force, Rumsfeld said: "No one is throwing down the gauntlet....I have nothing to announce. We're still dealing with Iraq."

Rumsfeld and Myers briefed reporters as American forces pushed into Baghdad with new freedom of movement. They were moving throughout the capital to seize and destroy buildings, having abandoned the brief in-and-out forays into Baghdad begun over the weekend to clean out resistance in the capital piece-by-piece.

The Defense Department briefed senators on the fast-moving developments.

"It's a matter of time," Sen. John Warner, R-Va., chairman of Armed Services Committee, said after the closed-door meeting on Capitol Hill.

"It's obvious that the end is near," said Sen. Carl Levin of Michigan, top Democrat on Armed Services Committee.

One question, for instance, was what would happen in Baghdad's residential areas, where officials say it is possible some Iraqi forces have taken refuge and could try to regroup.

Another was whether the greater ability to move around would help coalition forces find Saddam and other leadership figures who may still be alive, the eight missing and seven captured American soldiers, and the weapons of mass destruction the Bush administration said were the reason for waging the war.

At police stations, universities, government ministries, the headquarters of the Iraq Olympic Committee, looters unhindered by any police presence made off with computers, furniture, even military jeeps. Iraqis danced in the streets, waving rifles, palm fronds and flags, thrusting their arms in the air and flashing the V-for-victory sign.

Some of Saddam's forces were still in his birthplace and northern stronghold of Tikrit, some 100 miles north of Baghdad, and U.S. special forces were engaging them, defense officials said.

One official said it was possible that remaining regime officials could try to make a last stand in Tikrit.

A relatively smaller ground component of special operations forces was working with local Kurdish fighting forces in the north. The coalition has been using air strikes nightly in an effort to degrade military units there.