The United Nations Children's Fund, UNICEF, has postponed a long-planned polio immunization campaign for children in Afghanistan. The three-day campaign was supposed to take place early next week.

UNICEF had planned to vaccinate up to 5.7 million children under the age of five against polio. UNICEF spokesman, Marc Vergara, said because of the present crisis, it became impossible to go ahead. "We postponed the campaign because people are on the move and it is very difficult to vaccinate people when they are on the move," he said. "And, also we had to think, we work a lot with volunteers, what we call social mobilizers. These people have to make decisions about their own lives, their own families, their own security. These people are fleeing as well. So, it became impossible to organize this campaign," which had been scheduled for September 23-26.

UNICEF, along with all other U.N. agencies, has pulled its foreign aid workers out of Afghanistan fearing a United States' response for last week's terrorist attacks.

UNICEF's 70 local Afghan workers are continuing humanitarian operations in the country. But, Mr. Vergara said most operations have been reduced and only basic life-saving programs are going ahead.

For instance, Mr. Vergara said the local staff is carrying out a measles campaign in Afghan provinces most affected by drought and conflict. He said the campaign aims to reach about 2.5 million children aged six months to 15 years. He said some water and sanitation programs in camps for internally displaced people are continuing, as are nutritional programs for thousands of severely malnourished children.

The UNICEF spokesman said it is becoming more difficult for the Afghan workers to operate because of lack of transportation and concern for their personal safety. "Some staff, which are close to the border areas, might think that it is too dangerous for the family to stay in Khandahar or Kabul or whatever might be a city at risk," he said. "According to events, they might decide to move. We can not force them to stay. We would like the programs to continue. But, we understand that security is a prime concern. We fully agree with that."

Mr. Vergara warns that all humanitarian operations in Afghanistan will halt if the United Nations expatriate staff has to stay outside the country for several months.