A US official said militants planned to attack foreigners delivering aid to the millions of people affected by the devastating floods in the country.

One Taliban spokesman told Associated Press that the presence of foreign aid workers was "unacceptable".

The UN's emergency relief co-ordinator, John Holmes, said on August 26 that its security experts would be working with other international organisations "to assess what the risks are and to minimise them".

Mr Holmes noted that Tehrik-e Taliban had carried out a suicide attack on the office of the World Food Program in Islamabad last October, killing five staff.

However, there have been no attacks since the humanitarian crisis unfolded. The UN says more than 17 million people have been affected by the floods, and about 1.2 million homes have been destroyed, leaving five million people homeless.

Mr Holmes said UN agencies had provided almost 2 million Pakistanis with emergency food supplies and 2.5 million with clean drinking water. About US$325 million of the US$459 million sought by the UN in a Flash Appeal had been either contributed of pledged by foreign donors, while an additional US$600 million has been provided or promised outside the appeal, Mr Holmes said.

The US Agency for International Development (USAid) says that it has so far provided about US$150 million in support to victims of the flood.