By Kim Ghattas BBC correspondent in Baghdad

UN weapons inspectors are back in action in Iraq this morning, carrying out the first such inspections for four years.

The 17 UN experts left the Al Hyatt Tower Hotel early and headed to their re-established headquarters in the former Canal Hotel.

Equipment was prepared and inspected earlier and awaited them in a state of readiness.

It was a scene of near-pandemonium as cars tried - some in vain - to keep up with the high-speed convoy

Following their briefings the inspectors split into two teams to begin their work - one included nuclear experts, the other biological experts.

They left the compound accompanied by officials from Iraq's national monitoring directorate and headed in their different directions to target the already identified sites.

Element of surprise

The UN's land cruisers driving at high speeds were followed by over 50 cars, packed with journalists eager to find out where the inspectors were heading.

Many journalists had been staking out both the inspectors' hotel and the UN compound from very early morning, not wanting to miss out on the beginning of the operations.

Iraq must prove it has no weapons of mass destruction

It was a scene of near-pandemonium as cars tried - some in vain - to keep up with the high-speed convoy.

Until the last minute, the location of the inspection remained unknown.

The inspectors said the element of surprise was crucial for their work.

Team leader Jacques Baute said the more unannounced visits, the more credible the results to the UN Security Council.

One of the teams chose a site thought to be called Al Faldalia, a former women's prison on the north outskirts of the city.

The inspectors were greeted cordially by the Iraqis there and gained easy access to the area which measured about 300 x 300 metres.

Some journalists from the large media scrum were initially allowed in too, but Iraqi officials then pushed them out again.

UNMOVIC has warned it will impose a freeze on all movements during the inspection

The inspectors have made it clear they will not allow journalists on the sites during their inspections.

They said they wanted to keep as much distance as possible between them and the media

Within minutes of the inspectors' arrival, three cars full of Iraqi intelligence staff drove up. They pushed through the waiting journalists at the perimeter and monitored the actions of the inspectors.

Partial picture

The inspectors have said they expected full co-operation from the Iraqis and said that with the world watching, they should not play the hide-and-seek games that were common during the inspections of the 1990's.

Unmovic has warned it will impose a freeze on all movements during the inspection of a site to prevent any incriminating documents or equipment from being taken away

But Iraq continues to maintain the UN teams will find nothing.

The convoy was pursued by journalists in about 50 cars

Hans Blix, the chief UN inspector, has said it will be up to Iraq to prove it has no weapons of mass destruction - and to that end Iraq has to provide a full record of all their chemical, biological and nuclear weapons by 8 December.

The UN inspectors have 60 days to report back to the UN Security Council, although a spokeswoman said this report would only provide a partial picture.

Wednesday's inspections were small, but highly symbolic at two non-controversial sites.

It is the start of a long and slow process in searching hundreds of venues across this sprawling country. It is thought the inspections will take up to a year to complete.

Epic traffic jam

There are only 17 inspectors currently in Baghdad - 11 are members of UNMOVIC and six are experts from the Atomic Energy Authority, but up to 100 others are preparing to join them in their mission by the end of the year.

Their work has received little attention in the state-run Iraqi media. On Tuesday some publications did make reference to the inspections, but they are not making the headlines.

For the ordinary people of Baghdad, it is not the inspectors who are the talk of the town. However the terrible traffic jam caused by the convoy at about 0830 alerted the population to the fact that something is now happening.