Brigadier General Vincent Brooks said no Iraqi leaders were found in the Thar Thar palace, but he insisted the mission was a success and the commandos extracted safely after searching the complex and uncovering a "considerable amount of information" overnight Wednesday.

"It is a known residence that is used by Saddam Hussein and his sons ... The raid did not yield any regime officials but documents were seized," he told a briefing at US Central Command headquarters here.

"The regime moves from place to place, regime leaders move from place to place and we track them when we can. In this case we didn't find them but that's alright -- there are other operations that are ongoing."

Grainy night-goggle footage of the raid showed the commandos taking fire from anti-aircraft positions around the palace, some 90 kilometers (60 miles) outside Baghdad, as they descended in Chinook helicopters under the cover of darkness.

"They did take anti-aircraft fire on entry. An aerial gunship provided some support as required," Brooks said.

Meanwhile another commando team had occupied the Hadithah dam, about 200 kilometres northwest of Baghdad near Saddam's heartland of Tikrit, to prevent its destruction by Iraqi forces, he said.

Rather than extracting, these troops were holding the dam and waiting for support in the face of artillery and mortar fire from nearby Iraqi positions.

In other operations, US officers said two headquaters of Saddam's ruling Baath party had been raided near Baghdad as marines, mechanised infantry and airborne troops advanced across a massive front to the south.

Major General Buford Blount, commander of the 20,000-strong Third Infantry Division, said troops of his second brigade controlled a key intersection south of Baghdad and were 15 kilometers from the city center.

Brooks refused to confirm exact locations or comment on when US forces would enter the city itself, and warned that a lot of fighting lay ahead before the US-led coalition could lay claim to Baghdad.

"We are certainly in close proximity of Baghdad. I wouldn't want to characterise how close or how soon it will be before we arrive at certain points in Baghdad," he said.

"There will still be fighting ahead. We should be sober about our approach and about what we will do."

But the general seemed unable or unwilling to explain the condition of elite Republican Guard divisions defending the city.

He also sidestepped repeated questions about whether the there was evidence that Iraqi forces were withdrawing to make a last stand in the relative security of Baghdad's suburbs, as the Iraqi military has promised.

"Time will have to tell as to exactly the level of damage that has been inflicted. It's not a precise science, it's more of an art than a science in this case," he said.

"As to what is inside of Baghdad -- we'll see. Has the regime extended all of its capability in other areas? Did they use too much of what they had against us? One would have to speculate on that.

"We know that we inflicted some damage, there's no question about that. We know there are some that have pulled out of some their positions and tried to move to different places.

"We don't want to be overconfident with what we're seeing. There will still, we believe, be fighting ahead," he repeated.

SPACE.WIRE