Sudanese authorities re-arrested a woman on Tuesday hours after she was freed from a death sentence for converting to Christianity from Islam.
It was unclear why Mariam Yahya Ibrahim was detained as she tried to board a flight at Khartoum airport, but her lawyer said he expected her to be released by Wednesday.
A security official who confirmed the arrest said he did know why it had happened. Two diplomats said Ibrahim, her husband and two children were trying to get to the United States, via Cairo or Juba. All four were detained.
Ibrahim, 27, was freed by an appeal court on Monday which cancelled her death sentence after the government came under what it called unprecedented pressure.
One of Ibrahim's lawyers, Mohaned Mostafa, said he expected Ibrahim to be released by Wednesday. Another lawyer, said she and her family were being held at a security building near the airport.
After her release on Monday, she was sent to a secret location for her protection after her family reported receiving threats.
The US embassy in Khartoum said in a short statement that it was aware of Ibrahim's re-arrest and was in contact with her family and closely monitoring the situation.
The United States has imposed economic sanctions on Sudan since 1997 over alleged human rights violations. It intensified sanctions in 2006 over Khartoum's actions in its conflict with rebels in the western region of Darfur.
(Reporting by Maaz Alnugomi; Writing by Yasmine Saleh; Editing by Robin Pomeroy)