Less than 24 hours after the attacks, two staff members of the UN Special Mission to Afghanistan (UNSMA) were shot at by an unidentified gunman, prompting Secretary-General Kofi Annan to strongly condemn the ``heinous crime'' against international civil servants.

Annan said that in view of the new developments, he was reviewing all security arrangements for UN staff in Afghanistan, including relief workers from the UN children's fund (UNICEF), the World Food Programme (WFP) and the UN High Commissioner for Refugees (UNHCR).

The Secretary-General reminded the ruling Taliban authorities in Kabul that they were solely responsible for the security and safety of all members of the United Nations and non-governmental organisations (NGOs) operating in Afghanistan.

Annan said he wanted an investigation ofthe circumstances under which the UN staffers were attacked and he called for ``urgent steps'' to track down the attackers.

In a front-page story yesterday, the London Times said that dozens of aid workers who are still in Afghanistan were ``potential victims'' of any backlash against foreigners following Thursday's attacks by US warships, which rained missiles on a site there. The United States also bombarded a chemical plant in Khartoum, Sudan.

Thursday's attacks targetted installations which, according to Washington, were linked to Osama Bin Laden, a Saudi businessman whom the United States accuses of funding a network of terrorist groups and of being responsible for the August 7 bombings of the US embassies in Nairobi and Dar Es Salaam.

Washington alleged that the target in Khartoum was a facility that manufactured a substance used in chemical warfare. However, this was denied by Sudan's government, which claimed that the plant produced pharmaceutical drugs. The site attacked in Afghanistanwas used as a training camp by Bin Laden's network, according to the US.

UN spokesman Fred Eckhard said the United Nations was preparing to move UN staff from Afghanistan, on an individual basis, should they wish to leave. ``All non-essential travel inside Afghanistan had been suspended to reduce risk to staff,'' he told reporters, adding that the United Nations itself had not received any specific threats.

Eckhard also said that the United Nations continued to operate inside Afghanistan, and that all its programmes were continuing. All relief work in Afghanistan is being overseen by the UN office for the coordination of humanitarian operations.

There was also no indication that the attack against Sudan would stop relief work in Sudan by the United Nations' food relief consortium, Operation Lifeline Sudan (OLS), which operates humanitarian flights into southern Sudan.

The California-based world vision international, which is a member of OLS, said yesterday that it remained fully committed to helpingto save the lives of starving people in southern Sudan, despite the threat of reprisals following the US attack on a chemical plant in Khartoum.

``Too many Sudanese are hungry - desperately hungry - for us to turn away,'' Dean Hirsch, head of World Vision International, said. ``The situation remains critical for the 2.8 million people in southern Sudan. Their tragic situation must not be exacerbated by any potential retaliation to Thursday's bombings.''

Hirsch said that, on the advice of UN staff, all US nationals working for his organisation are serving in areas not held by the government of Sudan. In addition, all world vision staff flying in Sudan will travel only on UN-marked air planes.

Most of the aid workers in southern Sudan, however, are Sudanese.