The International Committee of Red Cross has facilitated regular prisoner transfers and exchanges between the army and RSF.
The Red Cross said Monday it had facilitated the release of 64 Sudanese soldiers held by paramilitaries, as the rival sides meet in Saudi Arabia over six months into war.
The forces of Sudan's army chief Abdel Fattah al-Burhan and his former deputy, paramilitary commander Mohamed Hamdan Daglo, have been locked in deadly fighting since mid-April, killing more than 9,000 people and displacing nearly six million.
The International Committee of the Red Cross has facilitated regular prisoner transfers and exchanges between the army and Daglo's Rapid Support Forces (RSF), with the latest swap one of the largest.
"Those released were transferred from Khartoum to Wad Madani," a major city south of the capital "at the request of both parties to the conflict", the humanitarian organisation said in a statement.
Representatives of the rival generals are currently in Saudi Arabia, where US and Saudi mediators have resumed negotiations aimed at a ceasefire and securing the delivery of desperately needed humanitarian aid.
Previous truces have been systematically violated, and the warring parties have traded accusations of obstructing humanitarian access.
Both the army and the RSF have been accused of operating detention centres with rampant abuse of those they have captured -- rival fighters as well as civilians.
There are no conclusive figures on how many are currently detained in Sudan, but the ICRC says it has facilitated the transfer and release of "292 detainees" since April.