The onslaught by British forces is said to be 'going well' so far

Royal Marines assisted US troops in entering the key southern Iraqi port of Umm Qasr.

Chief of the Defence Staff Admiral Sir Michael Boyce said the strategic deepwater port had been "overwhelmed" by coalition forces and would be used for humanitarian supplies in the next few days.

Coalition forces had come under strong attack and launched a heavy onslaught before entering the port.

British mine sweepers have been clearing routes to the port for shipping and Iraqi vessels carrying mines were seized.

US-led troops are also approaching the major southern city of Basra, with British units on the right flank "on the outskirts of Basra itself".

Soldiers from the Black Watch and the 1st Battalion Royal Fusiliers had seen "lots of evidence of large-scale Iraqi capitulation evidenced by abandoned positions and items of equipment", Sir Michael said.

Burning oil

Earlier Royal Marines were involved in an assault from helicopters to take control of important strategic oil stations in the al-Faw peninsula in southern Iraq.

And to the south and east of Basra, British forces assisted US troops in seizing much of the country's southern oilfields.

Sir Michael said: "They have done very well. They encountered some determined pockets of resistance, but have now reached the River Euphrates.

"All the key components of the southern oil fields are now safe."

It was reported that coalition forces discovered 30 oil wells had been set ablaze by retreating Iraqis, but Sir Michael said this figure had been revised down to seven.

He said the confusion had partly stemmed from an Iraqi military practice of filling trenches with burning oil as a defensive measure.

By first light Iraqi soldiers were surrendering in their dozens BBC's Clive Myrie Click here for full story of oilfields capture

Sir Michael said the men of 40 Commando had taken the surrender of Iraqi troops "in very significant numbers" at al-Faw.

And he said it was impossible to say how many more had simply abandoned their positions and run away.

Sir Michael said the attack on al-Faw was supported by RAF Tornado GR4s, which attacked enemy artillery with precision weapons, as well as targeting military installations as far north as al-Kut, about 100 miles south of Baghdad.

The admiral said RAF Harrier GR7s have provided air support for other operations, while E3-D airborne command aircraft, Tristar and VC-10 tankers and Canberra reconnaissance planes have also been involved.

Sir Michael also outlined British involvement in the initial air strikes on Iraq, saying several Tomahawk cruise missiles had been fired from British submarines at command and control centres in Baghdad and had hit their targets as planned.

He told a news conference in London: "It is very early days, but I have to say the coalition progress so far has been promising.

"I think our people have performed admirably on land, on sea and in the air and I am very encouraged by the start we have made."

British soldiers from the 15th US Marine Expeditionary Unit entered Umm Qsar - Iraq's largest commercial port - at about midday (GMT) on Friday.

Click here for more on the Royal Marines

The troops, working with Royal Marines, did come under fire and destroyed a company-sized Iraqi force on the way. It is not yet clear how many Iraqi troops were killed.

The port of Umm Qasr is seen as vital to the economic future of southern Iraq.

The British onslaught also involved tanks, troop carriers and infantrymen from the 7th Armoured Brigade - the famous Desert Rats - who entered south-eastern Iraq on Friday.

Prime Minister Tony Blair said on Friday the campaign appeared to be going well, but he expressed sympathy and praise for the first British casualties in a helicopter crash during the assault on al-Faw.

Defence Secretary Geoff Hoon confirmed eight British personnel had been killed when a US CH-46 helicopter crashed nine miles south of the border with Iraq.

MoD Helpline Numbers Royal Navy and Royal Marines - 08457 414544 Army personnel - 01980 615500 RAF personnel - 01452 712612 ext 7080 or 7045

Offering his condolences, he said it was still unclear what the cause of the crash was although it was "not the result of enemy action".

In Britain, eight US B-52 bombers took off on Friday from RAF Fairford in Gloucestershire.