Combined forces of Sudan People's Liberation Army (SPLA), Uganda People's Defence Forces (UPDF), Sudan People's Liberation Army-North (SPLA-N), and Justice and Equality Movement (JEM) have captured Nasir and Bentiu from anti-government forces just days after President Kiir agreed to meet rebels' leader, Dr. Riek Machar.
SPLA spokesperson Philip Aguer told reporters that soldiers loyal to President Salva Kiir have taken Nasir from the opposition forces, adding that Juba also recaptured Unity State's capital, Bentiu.
Aguer also denied that Sudanese rebels participated in the operations.
Rebels warned government forces
However, rebels' source told the South Sudan News Agency that they were not defeated in both Nasir and Bentiu; asserting that it was a "tactical withdrawal".
"We knew they [SPLA, UPDF,JEM, and SPLA-N] were coming, our intelligence agents alerted us long before they were sent to our areas, we made a tactical withdrawal, and we are going to teach them a lesson they will never forget", an official close to the rebels' leadership told the South Sudan News Agency.
"Just wait you will hear a different story soon. They are going to regret their premature victories and they will face dire consequences", he warned.
Nasir is the Upper Nile State's most popular county and Bentiu is the capital of the oil-rich Unity State.
In a separate development, Unity State rebels' commander Maj. Gen. Koang Chuol Ranley struck a similar tone saying his troops are not defeated and that Juba-backed forces will be punished soon.
Earlier this week, US Secretary of State John Kerry warned of "South Sudan Genocide" and called for a speedy peaceful solution to the conflict.
Peace talks are expected to resume next week in the Ethiopian capital, Addis Ababa.