“The judge sentenced them to death by hanging on charges of terrorism, fighting the state, bearing arms against the state and undermining the constitutional order,” Mahjoub Dawoud, defense attorney, told Reuters.
The defendants belong to the Justice and Equality Movement, a rebel group based in Darfur that took up arms against the Sudanese government in 2003, complaining that their region was being marginalized.
The group, led by Bakhit Abdul Karim (Dabjo), signed a peace agreement with the Khartoum government in 2013.
Shortly after the agreement, the group handed in its weapons to the government and in return the Sudanese president, Omar Hassan al-Bashir, pardoned members of the group.
However, the presidential pardon did not include the 25 South Sudanese nationals. The government considered them foreign fighters and brought them to trial for bearing arms against Sudan.
Lawyers of the defendants said they will appeal the court decision next week, calling the Sudanese authorities to treat their clients as prisoners of war.
Sudan regularly accuses its neighbor of backing insurgents in its Darfur, Blue Nile and South Kordofan regions.
South Sudan, which split away from Sudan in 2011 after decades of civil war fueled by ethnicity and oil, dismisses the allegations and accuses Khartoum of arming militias in its territory.