A Sudanese rebel group has freed 127 people it had captured in fighting with government forces, according to the country's army.

Those released by the Sudan People's Liberation Movement-North (SPLM-N) included 109 soldiers and 18 civilians, Brigadier Ahmed Khalifa al-Shami, the army spokesman, said in a statement on Sunday.

"The Sudanese army recognises this as a positive step towards achieving peace in the country."

The SPLM-N had captured the prisoners in Blue Nile and South Kordofan states, where the group has been fighting Sudanese government forces for years.

It was not clear how long the prisoners spent in captivity.

In 2011, South Sudan gained independence from Sudan following a 2005 peace deal that ended Africa's longest-running civil war.

Excluded from deal

After a referendum, in which an overwhelming majority of South Sudanese voted to secede, Africa's newest country came into being, the first since Eritrea split from Ethiopia in 1993.

But South Kordofan and Blue Nile, whose residents predominantly wanted to become citizens of the new nation, were excluded from the deal.

The SPLM-N, the northern affiliate of SPLM in South Sudan, consequently took up arms against the Sudanese government of President Omar al-Bashir, and fighting has continued on and off ever since.

Fighting in the two areas, and in Darfur, have left tens of thousands of people dead and displaced millions.

Khartoum announced a unilateral ceasefire in June 2016 in all three conflict zones, which it extended by six months in January.

UN says that for years Blue Nile and South Kordofan have been no-go areas for aid officials, leaving thousands of people without access to humanitarian relief.