Updated

The United Nations and several foreign aid organizations completed a swift withdrawal from Afghanistan on Thursday, fearing a U.S. strike on targets associated with Usama bin Laden, a leading suspect in the terror attacks on the United States.

A group of foreigners who left Kabul's war-ruined airport aboard three U.N. aircraft included relatives of two American aid workers who are being tried by the devout Muslim nation's hard-line Taliban rulers on charges of preaching Christianity. Six of their fellow workers — four Germans and two Australians — are also being prosecuted.

American Deborah Oddy, the mother of 24-year-old defendant Heather Mercer, held a mandatory shawl tight around her head, her eyes brimming with tears. She only had been allowed one visit with her daughter since arriving in Afghanistan on Tuesday, hours before the attacks on New York and Washington.

Heather's father, John Mercer, left very reluctantly. Until late Wednesday, he said he was determined to stay, but in the end he left along with David Donahue, consul-general of the U.S. Embassy in neighboring Pakistan. Mercer wouldn't talk as he boarded the aircraft.

Nancy Cassell, the mother of American Dayna Curry, 29, also left. She had seen her daughter five times since arriving more than two weeks ago.

Cassell and Oddy wrote farewell letters to their daughters on Wednesday. They said it was a devastating experience.

Aboard the three U.N. aircraft were about 35 international aid workers, the relatives of the detained Americans, a handful of journalists and three diplomats — including Donahue — who had been seeking information about the Taliban case against their compatriots.

The International Red Cross evacuated its nonessential staff members, saying it would continue to evaluate the safety of those who remained. All other Western aid workers are believed to have left Afghanistan.

"I don't feel well about leaving. It is unfortunate, but it is due to the situation. I cannot change it," said Helmut Landes, of the German Embassy in Pakistan. Australian diplomat Alastar Adams also left.

A Pakistani lawyer for the detained aid workers, whose trial is under way in beleaguered Kabul, was expected to arrive Saturday. The diplomats would not identify him, but he was described as an Islamic scholar and alumnus at one of the religious schools in Pakistan that many Taliban leaders have attended.

Several Arabs and their families also left. At least three families were seen heading out of Kabul, their destinations unknown.