UN convoys have started to fan out in southern areas near the border with Kuwait and in Kurdish-controlled regions in the north of the country, officials said.

The International Committee of the Red Cross (ICRC) was trying to provide medical help for war wounded and water supplies in Baghdad as well as around the southern city of Basra and Arbil in northern Iraq.

But a World Health Organisation (WHO) truck carrying 13 tonnes of medical supplies from Jordan for the first time since the war started 22 days ago was forced to take cover in Baghdad because of unrest, WHO spokesman Iain Simpson told AFP.

Areas around the route of the US-led coalition's offensive on the Iraqi capital, including the central cities of Najaf and Karbala were still not being reached, according to the ICRC.

"We know that there are important emergency needs in hospitals and for water and sanitation there," ICRC spokeswoman Antonella Notari said.

Notari said the security vacuum after the collapse of Iraqi president Saddam Hussein's regime needed to be filled rapidly.

"It's a de-facto occupation. As soon as there is control of certain part of the territory, as an occupation force you become responsible for the security and well-being of the population," Notari said.

"I don't think it means they need to directly take care of all the distribution and repairs -- although it's great if they do and have the means. But there are people capable of doing that, and the occupation forces can facilitate their work," she added.

The WHO spokesman also said occupying US forces needed to respond to the situation in Baghdad, with doctors, patients and aid cut off from hospitals which were running critically short of water, electricity and supplies.

"Law and order is the big thing that has to be sorted out soon," he said.

Security conditions ranged from uncertainty in Basra to chaos in parts of Baghdad, because of pockets of fighting and looting, according to the ICRC.

"The biggest problem in Basra really is that we had managed to get water supply up again to 90 percent for about 1.8 million people, and then the looters ransacked the water pipes," Notari said.

The United Nations said that about 720 million dollars worth of emergency supplies were heading towards Iraq by boat and by road.

Led by the UN Children's Fund UNICEF, UN aid agencies set foot in southern Iraq last Friday, allowing convoys carrying water to follow from Kuwait. Most of the deliveries took place around the deep water port of Umm Qasr in the south, said Elizabeth Byrs, spokeswoman for the UN aid coordinator.

The World Food Programme (WFP) resumed food deliveries from Turkey into in northern Iraq on April 4.

The United Nations wants to reactivate about 40,000 food distribution points set up in Iraq under the oil-for-food programme, which was suspended by the United Nations shortly before the war.

Iraq's neighbours -- Iran, Jordan, Kuwait, Syria, and Turkey -- have offered to open ports and roads to supplies, according to the head of the UN's oil-for-food programme, Benon Sevan.

About 55 non-governmental organisations have said they are ready to work in Iraq, while offers of government aid have flowed in from the European Commission, Denmark, Germany, Egypt, Greece and the Philippines.

US Defence Secretary Donald Rumsfeld said Wednesday that aircraft have delivered aid supplies to the Baghdad international airport.

Several NGO aid groups asked the UN Security Council on Wednesday to assure them free access to Iraqis in need of humanitarian assistance.

The aid community's concerns matched those of Iraqi opposition leader Ahmad Chalabi, who on Wednesday urged Washington's nominated head of a civilian administration in Iraq to intervene and ensure that stability was restored.

SPACE.WIRE