Meriam Yahia Ibrahim Ishag sits in her cell at a women's prison in Omdurman, on May 28, 2014 after giving birth to a baby girl
Khartoum (AFP) - A Sudanese Christian woman was detained at Khartoum airport on Tuesday, one day after an Islamic court annulled her death sentence for apostasy and released her from prison.
The exact status of 26-year-old Meriam Yahia Ibrahim Ishag after officials took her back into custody was unclear.
US officials said they had received assurances that she had not been arrested and would be allowed to leave, but a Sudanese source said she was being investigated for carrying fake documents.
"The National Security took her and Daniel," said the source, referring to Ishag's American husband Daniel Wani, who was supposed to be travelling with her.
Later, the same source told AFP that Ishag had been transferred from the custody of the powerful National Intelligence and Security Service to an ordinary police station.
She is under investigation there but has not been charged, he said. Her husband and children are with her but are not themselves suspected of wrongdoing, he added.
Meanwhile, in Washington, State Department spokeswoman Marie Harf downplayed the incident and said US officials would work with Khartoum to ensure the family would soon be on its way.
Harf said Sudan had said that "the family was temporarily detained at the airport for several hours by the government for questioning about issues related to their travel and, I think, travel documents.
"They have not been arrested," she added. "The government has assured us of their safety. The embassy has and will remain highly involved in working with the family and the government."
Sudan's Information Minister Ahmed Bilal Osman told AFP he was not familiar with the latest developments and could not comment.
Ishag's case sparked an outcry from Western governments and human rights groups after a lower-court judge sentenced her to death for apostasy on May 15.
Born to a Muslim father and an Ethiopian Orthodox Christian mother, Ishag was convicted under Islamic sharia law that has been in force in Sudan since 1983 and outlaws conversions on pain of death.
When Ishag was five, her father abandoned the family, and she was raised according to her mother's faith.
The Roman Catholic Archdiocese of Khartoum said she joined the Catholic church shortly before she married.
"She has never been a Muslim in her life," the church said.
- Fears for her life -
After the appeal courts quashed the earlier verdict, Ishag went into hiding fearing for her life because of death threats, one of her lawyers said.
"She is in a safe place. I will not tell you where," Mohanad Mustafa told AFP on Monday night. "The main reason is that we are concerned about her life."
He and other members of Ishag's legal team have also been threatened.
Ishag and Wani were detained at roughly the same time the United Nations independent expert on human rights in Sudan, Mashood Adebayo Baderin, held a press conference in Khartoum.
He said that if she had received death threats, "as a citizen of this country, the Sudan has a duty to protect its citizens."
Baderin, who had visited Ishag in prison, agreed that the case "raises important legal questions about the right to freedom of religion and belief."
Twelve days after the court issued its death sentence, Ishag gave birth to her baby daughter at the women's prison in Omdurman, where she was shackled during pregnancy, Mustafa said.
Mervyn Thomas, chief executive of Christian Solidarity Worldwide (CSW), said his group was delighted that "the unjust, inhumane and unwarranted sentences have been annulled."
But he said the British-based group, which works for religious freedom, was appalled at the "threats and hate speech."
"Her alleged brother has publicly stated the family would carry out the death sentence should the court acquit her," CSW said.
Muslim extremist groups had lobbied the Islamist government over Ishag's case, prominent newspaper editor Khalid Tigani has said.