Khartoum - A Sudanese Christian woman who faces death threats after a court cleared her of apostasy has been charged with forgery, after trying to leave the country, a lawyer said.
"She is arrested," Mohanad Mustafa told AFP on Wednesday.
The charge against Meriam Yahia Ibrahim Ishag, 26, relates to the South Sudanese travel document she was carrying when authorities stopped the family from leaving Sudan on Tuesday following an annulment of her apostasy death sentence.
Ishag is also charged with providing false information, Mustafa said.
She was detained by national security agents at Khartoum airport, despite the presence of US diplomats who were escorting her and her family, her American husband Daniel Wani said.
They were trying to travel to Washington, Wani said, insisting there was nothing wrong with the travel documents.
Sudan's ministry of foreign Affairs on Wednesday summoned the charges d'affaires of both the United States and South Sudan over the incident, official media reported.
US state department deputy spokesperson Marie Harf said Washington's charge d'affaires had voiced "our concern that the family should be allowed to depart swiftly from Sudan".
"Sudan has assured us of their -the family's safety... We will continue monitoring the situation and discussing it," she added.
Sudan's foreign ministry criticised South Sudan's issuing of the travel permit, "despite their knowledge that she is a Sudanese national", while condemning the US for trying to help the women leave Sudan "via illegal [false] travel document", the SUNA news agency said.
"We are worried. That's why we want to get out of here as soon as possible," Wani said of death threats against his wife.
A lower court judge sentenced Ishag to hang for apostasy on 15 May, in a case that raised questions of religious freedom and sparked an outcry from Western governments and human rights groups.
An appeal court freed her on Monday from the women's prison where she had been detained with her children, but she immediately went into hiding because of the threats to her life.
Information Minister Ahmed Bilal Osman told AFP the woman should have used a Sudanese passport, but her lawyer said she does not have one.
"That is the whole problem, she took a foreign document for travelling," he said. "What she has done is an illegal act."
However, Osman suggested the situation can be resolved.
A family 'problem'
Kau Nak, South Sudan's charge d'affaires, said Ishag was entitled to the travel document because her husband and children are South Sudanese.
"I'm the one who issued that travel document to her," he told AFP. "My signature is on the back of the document."
After being stopped at the airport, the family and its two children, including a baby girl born while Ishag was on death row, were taken to a police station, a two-storey building on a rough, unpaved alley in Khartoum's Arkawet district.
Ishag remains in custody there.
On May 15, a lower court judge, referring to her by her father's Muslim name Abrar al-Hadi Mohamed Abdalla, sentenced her to death for apostasy.
It convicted her under Islamic sharia law that has been in force in Sudan since 1983 and outlaws conversions on pain of death.
On Monday, an appeals court freed her from the women's prison where she had been detained with her children, but she immediately went into hiding.
'Problem is with her family'
Christian activists say her "alleged brother" stated that the family would carry out the death sentence if she were acquitted.
According to the church, Ishag was born to a Muslim father and an Ethiopian Orthodox Christian mother.
When Ishag was five her father abandoned the family, leaving her to be raised by her mother, according to the Roman Catholic Archdiocese of Khartoum, which said she joined the Catholic church shortly before she married.
It said the original legal action against her was filed by men "who claim to be" her relatives.
"The problem is not with the Sudanese government, is not with the court. The problem is with her family," said Information Minister Osman.