BASRA, Iraq, March 24 (IslamOnline.net & News Agencies) - Under attacks by mortars and guerrillas disguised in civilian clothes, Britain's Seventh Armored Brigade, the Desert Rats, was forced to withdraw Monday, March 24, from the southern Iraqi city of Basra, Iraq's second largest.

U.S.-led military commanders admitted they had vastly underestimated the strength of Iraqi resistance and the loyalty of Basra's population to the regime of Iraqi President Saddam Hussein, according to Agence-France Presse (AFP).

Fierce Iraqi resistance, including attacks by irregular forces pretending to surrender, forced invading British troops to withdraw from Basra to regroup, British military officials said.

"We're currently taking stock of the situation. We were expecting a lot of hands up from Iraqi soldiers and for the humanitarian operation in Basra to begin fairly quickly behind us," Captain Patrick Trueman said.

U.S. and British forces had a tough time taming Iraqi resistance in the country's southeast, outside Basra and the key deep-water port of Umm Qasr, reported AFP.

Military planners had expected little resistance in the region because they thought the Shiite Muslim majority long repressed by the Sunnis from the north would be glad to be rid of Saddam.

The brigade had at one point surrounded the city.

Military leaders were concerned that members of Saddam's Fedayeen had lured British troops into danger by pretending to surrender and by using women and children as decoys.

Members of the Fedayeen have taken to disguising themselves in civilian clothes, mixing with families then emerging from crowds to fire on the coalition forces, according to AFP.

"There are significant elements in Basra who are hugely loyal to the regime. Their loyalty is rewarded with a better standard of living than most, so they don't want to give it up easily," he added.

Trueman said, "We always had the idea that everyone in this area hated Saddam. Clearly, there are a number who don't."

The decision to withdraw came after British units came under fierce mortar fire as they blocked the main routes into the city from the north and south.

Military leaders were also concerned the Iraqis might use a captured British vehicle as a car bomb.

British Prime Minister Tony Blair told the House of Commons on Monday that the international airport of Basra had been "made secure".