A Sudanese Christian woman was arrested Tuesday at Khartoum airport a day after a court annulled her death sentence for apostasy and released her from prison, a source familiar with the incident said.
"The National Security took her and Daniel," said the source, referring to Meriam Yahia Ibrahim Ishag, 26, and her American husband Daniel Wani.
The status of their two young children, one a baby born in prison before Ishag's release, was not immediately known.
The couple were detained, for reasons that are unclear, at about 1100 GMT as they tried to leave the country, said the source.
He could not give more details except to say they were taken to a facility of the powerful National Intelligence and Security Service (NISS).
"She has the right to leave the country," the source said.
Ishag's case sparked an outcry from Western governments and rights groups after a lower-court judge sentenced her to death on May 15.
Almost one million people appealed to save her life on the Change.org petition website.
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," a statement said.
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."
Mustafa said Wani had been reunited with his wife, newborn baby and the couple's 20-month-old son who had been incarcerated with his mother.
"Now she is with her husband and their children in the safe place," said the lawyer.
He and other members of Ishag's legal team have also received death threats.
Twelve days after the lower court issued its death sentence, Ishag gave birth to her baby daughter at the women's prison in Khartoum's twin city of Omdurman, where she was shackled during pregnancy, Mustafa said.
Mervyn Thomas, chief executive of Christian Solidarity Worldwide (CSW), said the 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.
Amnesty International said she was released under international pressure, but Rabbie Abdelatti Ebaid, a senior official in Sudan's ruling National Congress Party, denied that.
Muslim scholars have divergent opinions on the issue of changing religion, and "jurisprudence in Islam is very broad," allowing for a solution, he told AFP.