Four men accused of espionage have been released by Sudanese authorities after three weeks of detention, officials have said.
The group - a Briton, a Norwegian, a South African and a South Sudanese citizen - were alleged to have entered an oil-producing border area illegally to spy for South Sudan.
The four appeared on Sunday at a brief ceremony in a defence ministry reception hall in the capital, Khartoum.
"The president of the republic decided to release them as a gesture of goodwill"
- Abdel Raheem Hussein, Sudan defence minister
None of them spoke about the allegations, which South Sudanese officials have strenuously denied. They also did not touch the soft drinks and water laid out before them.
Norwegian John Sorbo said authorities had treated them "very well" during their detention in a military facility in Khartoum.
"I'd just like to use the opportunity to thank [Sudanese officials] for the way they looked after us," he said.
Speaking alongside them, Abdel Raheem Hussein, Sudan's defence minister, said Khartoum had decided to release the four after talks with former South African president, Thabo Mbeki.
"We launched an investigation and had great doubts about their intentions, because they were arrested in a war zone," Hussein told reporters.
"They were working for one of the two sides," he said, without naming South Sudan directly. "The president of the republic decided to release them as a gesture of goodwill."
South Sudanese officials have denied Sudan's allegations, saying the men were working with the United Nations and aid groups clearing mines, and had got lost in the remote territory.
"We have spoken to Norwegian People's Aid, who have confirmed that one of their deminers had been arrested, along with a number of other demining workers who had been operating in that area," said Al Jazeera's Peter Greste, reporting from Juba on April 29, when the men were arrested.
The release of the four men came after a meeting late on Saturday between Sudan's President Omar Hassan al-Bashir and Mbeki, who is trying to bring the two Sudan's to African Union negotiations to end violence in oil-rich border areas.
|In-depth coverage of North-South strife over border
"We asked President Bashir to release you," Mbeki told the four at the ceremony. "All of us will go together."
Mbeki then left the defence ministry with the four men. He is due to fly to Juba on Sunday for talks with southern officials.
The arrest in April came after weeks of fighting that brought the two countries closer to an all-out war than at any time since South Sudan seceded last year.
The southern nation, which became independent in July 2011 under a 2005 peace deal that ended decades of civil war, had seized the disputed Heglig oil area earlier in April, but withdrew under heavy international pressure and facing counter-attacks from northern forces.
The neighbours are still in a dispute over a raft of contentious issues, including the exact definition of the border, the status of citizens in one another's territory and how much the landlocked South should pay to export its oil through Sudan.