British army Royal Engineers were besieged by more than a 100 people as they went to the scene in two tanks but had to tell the crowd they did not have the necessary equipment to begin an immediate search.

Some Iraqis could be seen with bloodied hands after digging through the bombed out wreckage while others tapped on a metal pipe in a bid to make contact with anyone below.

"They are prisoners, we heard the sound 'knock, knock, knock'," said Khalid Ahmed.

"We must dig a hole. They are underground. They are without food, water for 10 days -- they are going to die. These are people, not animals."

One officer with the Royal Engineers said it was impossible for the British to offer immediate help.

"There are too many people. We need to get the proper equipment," he yelled to the crowd through an interpreter.

A sergeant said that people had told him they had heard banging from underground although it was impossible to verify the claims.

"We do not know if it's all just a rumour," he said.

"People have digging with their hands, cutting their hands and they tried to lower someone through a hole feet first.

"We can try to look where the entrances are and see if there's been much damage."

One onlooker, Jassen Hamed, said that he believed Kuwaitis taken prisoner after the Iraqi invasion of its southern neighbour in 1990 were in the underground cells.

"My brother was here in prison two years ago. He said there were 200 Kuwaitis here," he said, gesturing handcuffs.

Around 600 Kuwaitis are still missing in the aftermath of the occupation, and the emirate's government has made information on their fate one of its top priorities for relations with the post-Saddam Hussein regime in Baghdad.

Student Hisham Zaki said he believed Islamic fundamentalists who had fallen foul of Saddam's secular Baath party were also being held in the prison.

Others insisted that they had heard women's voices from below.

By nightfall the crowds had dispersed along with the British troops who took control of Iraq's second city a week earlier this week.

The area around the prison which adjoined the city's court house and main police station was dotted with bomb craters as a result of the bid by coalition troops to wrest control from militias loyal to the Iraqi leader.

The buildings were ransacked by locals in the aftermath of the downfall of the ruling party in Basra, and the ground was littered with documents.

Locals said that the prison had been largely empty before the start of the war on March 20. Saddam granted a mass amnesty for prisoners last October as conflict became increasingly likely.

SPACE.WIRE