Gangs of looters, many of them armed, roamed the streets of Baghdad on Thursday, ransacking offices and government buildings as US troops looked on and breaking into the houses of Saddam Hussein's top aides.

Looters drove tractors, pick-up trucks and trailers -- and even a large bus -- up to a large villa belonging to Tareq Aziz, Saddam's deputy prime minister.

They stole everything from furniture and paintings, to chandeliers and curtains, and stripped the electrical wires from the villa's main switchboard.

Aziz's library was also ransacked. Among the volumes left behind by looters were the complete works of Saddam in Arabic, a book on geopolitics by former US President Richard Nixon, and the Mafia novels of Mario Puzo, author of The Godfather.

Many of the looters were from the Saddam City area, home to about two million impoverished Shi'ite Muslims.

Asked why he was robbing the house, one man wordlessly pointed to his open mouth to indicate he was hungry.

The International Committee of the Red Cross said it was concerned about the looting of hospitals.

"The hospitals themselves have come under attack for the purpose of looting. There are lots of people carrying weapons around and they make it very difficult for civilians in need of medical care to actually reach the hospitals," ICRC spokesman Roland Huguenin-Benjamin in Baghdad told CNN.

A house in southern Bahdad belonging to Saddam's notorious cousin Ali Hassan al-Majid -- known as 'Chemical Ali' -- was also robbed.

Saddam had put Majid, nicknamed for overseeing the use of poison gas against Kurdish villagers in 1988, in charge of the defence of southern Iraq.

US forces say he may have been killed in a bomb attack in Basra at the weekend.

One man, who said he was an Iraqi poet and gave his name as Abu Eyaih, carried off two of Majid's walking sticks. He said he was taking the sticks as a gesture of contempt towards Majid, who sometimes walked with the aid of a stick.

"I'm not here to loot the house of this criminal Ali Hassan al-Majid. I took these two things as a symbol to humiliate him," he said. "I am feeling sad that some Iraqis are looting furniture and equipment of public buildings. They don't belong to Saddam, they are the property of the Iraqi people. We should keep them where they are for the new government to use when it assumes power."

The Ministry of Trade was set ablaze by looters, and flames could be seen pouring out of first floor windows of the building, close to the east bank of the River Tigris.

The finance ministry was also engulfed in fire on Wednesday.

A nearby Interior Ministry building housing an office for identity cards was also in flames, as people carted off furniture and computers.

Several diplomatic buildings were robbed, including the German embassy, the French cultural centre, and the house of the Finnish ambassador -- where one looter staggered out carrying an air-conditioning unit.