Thousands of Iraqi troops were reported to have surrendered in the wake of the Allied invasion into southern Iraq.

Iraq's 51st Infantry division, which consisted of 8,000 men and as many as 200 tanks, surrendered to coalition troops on Saturday morning.

Thousands more have laid down their arms as coalition forces seize control of major cities in southern Iraq.

Sporadic fighting, however, continued in some areas as a number of units loyal to Saddam offered resistance.

Military officials said on Saturday they were confident they had control of key Iraqi cities in the south, including the second city of Basra, as British and US forces were preparing to launch a second night of the Allies' "shock and awe" campaign against Saddam Hussein's regime.

Waves of bombers, jets and missiles struck targets in the Iraqi capital on Friday and bombers also hit targets in the northern cities of Mosul, Kirkuk and Tikrit, Saddam's hometown.

US troops have seized the the airport north of Basra and have taken key strategic bridges in the south.

To the north-west, US troops were reported to have secured the strategic town of Nassiriya.

Meanwhile, Allied forces led by the US 3rd Infantry Division were continuing their rapid march towards Baghdad.

US Defence Secretary Donald Rumsfeld said Saddam Hussein and his lieutenants were "starting to lose control of their country"

Speaking in Qatar, Air Marshal Brian Burridge, head of UK forces in the Gulf, said the next 24 hours could be the most important of the war.

He was satisfied with the war so far saying progress was "promising".

British Defence Secretary Geoff Hoon said "good progress" had been made in securing the Al Faw peninsula and Royal Marines had confirmed the oil infrastructure close to the Kuwaiti border had not been destroyed.

"Any attempt by Saddam Hussein to release oil into the Gulf to create an environmental disaster has been thwarted," said Mr Hoon.

Iraq in depth: iraq.usatoday.com