Squeezing his eyes tight to stop the tears, John Mercer said he pleaded Monday with the Taliban rulers to let him take the place of his 24-year-old daughter, Heather, jailed in Afghanistan on charges of preaching Christianity.

"I offered to go in place of my daughter," Mercer told a news conference in the Pakistani capital, stopping briefly to gain his composure." His head bowed, his voice shaking, Mercer said "it was a very serious offer. I would do it."

Mercer said he met Taliban authorities at the Afghan embassy in Islamabad and that they did not respond to his request. He was joined at the news conference by Heather's mother, Deborah Oddy; Oddy's husband, Delmer; and Tennessean Nancy Cassell, the mother of Dayna Curry, 29, the other American woman in jail in Afghanistan.

Mercer and other family members left Afghanistan on Thursday after the deadly terrorist attacks in the United States made it too risky to stay in the capital, Kabul. All foreign aid workers left over the weekend. Afghanistan is a possible target of retaliatory strikes from the West because the Taliban allow the prime suspect, Usama bin Laden, to live there.

Mercer and Cassell had been in Afghanistan for more than two weeks when they left. Mercer's mother, Deborah Oddy had arrived Sept. 11, the day of the attacks.

She saw her daughter that evening. That was the last visit any of them had with their children.

"I don't know if you have a child, but you can imagine what it must be like for a mother to leave her daughter in a situation like this. I can't describe it. It's a heartbreak," said Cassell, a teacher from Thompson's Station, Tenn.

Heather Mercer and Dayna Curry were arrested in early August along with six other foreign aid workers of the Christian-based Shelter Now International aid group on charges of preaching Christianity in this devoutly Muslim nation. The six other jailed aid workers are German and Australian.

Curry grew up in Tennessee, and her father, Tilden Curry, is dean of the business school at Tennessee State University at Nashville.

The aid workers have been held in a reform school in the center of Kabul by Taliban guards armed with Kalashnikov rifles.

Their trial began about three weeks ago, but only last week were they able to appear in court or hear the charges before them. The family hired a Pakistani lawyer before leaving Afghanistan, but the lawyer, who is versed in Islamic law, has been unable to get an Afghan visa to go to Kabul to meet with his new clients.

It's not clear when the trial will resume. In Kabul, the Taliban's chief justice said they were still reviewing the evidence and waiting for the lawyer of the eight aid workers to arrive.

Mercer said that he and Cassell have twice written to the Taliban's leader, Mullah Mohammed Omar, pleading with him to show mercy for their children, apologizing if the two women had offended anyone.

The parents said their children were motivated by a desire to help.

"I know in their mind, they went to Afghanistan to help the people. They worked very hard to go," said Mercer, of Vienna, Va.

Deborah Oddy, of Lewiston, N.Y., recalled her daughter's work at soup kitchens and collecting donations during the Christmas season to help the poor.

Before leaving Afghanistan, the parents wrote their children a farewell letter.

"We could only tell them that we were here and that we were working for them," Oddy said.

Mercer had been reluctant to leave Afghanistan and until the last minute he had resisted, but in the end he relented. He said he won't be leaving Pakistan — not without his daughter.

"This is as far as I am going without my daughter, come hell or high water," he said.