The Sudanese government has summoned both the United States and South Sudan ambassadors following the re-arrest of Christian convert Miriam Ibrahim over "forged" travel documents.
Sudan's National Intelligence and Security Services agency said that Ibrahim had attempted to travel to the US using an American visa and documents issued by South Sudan.
A post on Facebook, in which the agency referred to her using her Muslim name, read: "The airport passport police arrested Abrar after she presented emergency travel documents issued by the South Sudanese embassy and carrying an American visa."
"The Sudanese authorities considered (the action) a criminal violation, and the Foreign Ministry summoned the American and South Sudanese ambassadors," it added.
More top news
A team of detectives and specialists is set to begin a painstaking excavation of the area where Ben is thought to have gone missing in 1991.
The foreign secretary's suggestion last week's bombing of an aid convoy might constitute a war crime prompted an angry response from Moscow.
Goals from Charlie Austin, Dusan Tadic and James Ward-Prowse consigned Slaven Bilic's men to their fourth straight Premier League loss.