By Ben Brown BBC Baghdad

United Nations weapons inspectors in Iraq have completed their investigation at one of Saddam Hussein's presidential sites.

Iraqi guards kept them waiting at the gates for several minutes before finally allowing the inspectors in.

[The inspectors'] mission here in Iraq has now moved up a gear

The UN team spent around two hours inside the palace before returning to their headquarters in Baghdad.

In the past, the Iraqis have said their presidential palaces are off-limits but under the tough new UN mandate, the weapons inspectors are allowed to go where they want, when they want.

So when the inspectors turned up at the huge gates of the al-Sijood palace in Baghdad it was an acid test of Iraqi co-operation.

The palace has vast grounds

Initially, there was a scene of some chaos at this presidential site, a lot of shouting, a bit of arguing and some confusion.

The inspectors got on their radios, their walkie-talkies. It did not appear they were allowed access immediately.

But then the gates opened up and their convoy of white UN land cruisers rolled into the spectacular sprawling grounds.

Open doors

It was always going to be a real crunch for the weapons inspectors as to whether they could get access to these enormous, sprawling sites where Western intelligence agencies have alleged that weapons of mass destruction - or parts of them - could be hidden.

One UN car stayed parked by the gates, blocking them off so no-one could get in or out, sealing the palace off for the period of the inspection.

Journalists rushed into the palace

The UN team stayed for about two hours. It is not clear what they were looking for exactly nor what they found, or why they spent such a relatively short time there.

The Iraqis insist they have nothing to hide in palaces like this one.

More than anything this was a symbolic visit by the weapons inspectors but their mission here in Iraq has now moved up a gear.

Luxury retreat

After the inspectors left, the waiting journalists were invited in for a brief visit of our own to the presidential palace.

Its grounds are lavish, with an imposing drive that is lined by palm trees and that leads up to the three-story palace building.

Gardeners carried on with their work, tending the roses, as reporters ran towards the palace doorway in a chaotic, frenzied throng, almost tripping over ourselves to see inside.

We could hardly believe we were being allowed in.

What greeted us was a glimpse at the spectacularly beautiful entrance hall and then a sumptuous octagonal atrium, in the middle of which stood a table bearing a detailed scale model of the entire palace.

The atrium was carved white marble, illuminated by a vast gold and crystal chandelier.

Something for everyone

We were not shown any other parts of the palace and we were not allowed to stay for more than half an hour but the Iraqis seemed keen to open up this previously "sensitive" site not only to the inspectors, but also to the world's media.

It must be impossible to search a palace and grounds as vast as this in the course of less than two hours and presumably the inspectors will be back.

Even so, everyone gained something today: the weapons inspectors proved that nowhere is off-limits to them, the Iraqis showed they are co-operating with the United Nations and we journalists covering the crisis here managed a rare peek into some of the grandest architecture Iraq has to offer.