Sudan opposition leader Yasir Arman arrived in Juba, South Sudan on Monday after he was released together with two other rebel leaders by the military junta.
Mr. Arman is the deputy chairperson of the Sudan People's Liberation Movement/ Army- North (SPLM/A/N), an armed faction based in the Blue Nile region.
He had been arrested on June 5 by the Sudan's Transitional Military Council (TMC) for allegedly fuelling protests in the crisis-hit country.
He had earlier defied a military ultimatum that he leaves the country on accusations that he was positioning himself to become the President of Sudan with the help of foreign financiers.
The rebel leader was accused of enjoying foreign backing and positioning himself to become the President of the Sudan.
The release of the trio - the others are Ismail Jalab and Mubarak Ardol - is believed to have been negotiated by Ethiopian premier Ahmed Abiy who was on a reconciliation mission in Khartoum last week.
Mr Abiy met TMC, Alliance for Freedom and Change and other political leaders with a message that Sudan reverts to democratic rule.
Jalab and Ardol were detained from their residences after meeting with Mr Abiy Ahmed in Khartoum on Friday for talks aimed at reviving negotiations between the generals and protest leaders.