Authorities in Northern Upper Nile State said a number of South Sudanese employees have been arrested by Sudanese security agents since late October.

Speaking to Radio Tamazuj on Tuesday, the state information minister, Santino Nyuan said security forces from Sudan’s Sennar and Blue Nile States entered the border town of Adham, where they arrested 14 tax officials including their police escorts on October 13.

"The officials were on their way to Sesame schemes in two vehicles to collect tax, and were arrested by Sudanese security forces deep inside South Sudan territory at gunpoint without clear reasons," he said.

Three other tax officials, Nyuan added, were arrested in early November, bringing the total number of those in custody to 17.

The state minister said authorities in Sennar and Blue Nile states confirmed the arrest of South Sudanese tax officials and their police escorts.

Nyuan pointed out that the national government in Juba has been informed and is coordinating with Khartoum over the matter.

Sudanese officials could not immediately be reached for comment.

Sudan and South Sudan have recently indicated they are willing to deepen cooperation and promote bilateral ties, after a legacy of unstable relations between the two countries since 2011.