Addis Ababa - African nations mediating South Sudan's peace efforts must not "squander" the opportunity of a renewed push to end the country's war, the head of an international ceasefire monitoring team said on Saturday.
Festus Mogae, a former president of Botswana who leads the Joint Monitoring and Evaluation Commission (JMEC), urged members of the eight-nation IGAD trade bloc to work together.
Mogae said Djibouti, Eritrea, Ethiopia, Kenya, Somalia, Sudan and Uganda must "maintain a unified approach, demonstrate one voice (and) challenge those who peddle self-interest" in the implementation of a peace agreement.
A first round of talks to revitalise a 2015 peace agreement resulted in a ceasefire in December which lasted just hours before warring parties accused each other of breaking the truce.
The United Nations has described the latest peace push as a "last chance" to end South Sudan's four year civil war. A second round of talks is expected on February 5.
Mogae, speaking at an African Union summit in Ethiopia, said the process was a "watershed and offers an opportunity that should not be wasted or squandered," according to a JMEC statement.
Analysts say the regional interests of the IGAD members are often wildly different.
South Sudan descended into war in December 2013 when President Salva Kiir accused his former deputy Riek Machar of plotting a coup.
A peace deal was signed two years later but collapsed in July 2016 when fresh fighting in the capital Juba forced Machar into exile. The renewed violence spread across the country, with new armed opposition groups forming.
Last week Mogae called for "consequences" for those who refuse to turn away from the battlefield.
"We cannot stand by as South Sudanese leaders sign an agreement one day and authorize or allow its violation with impunity the next," Mogae told the Security Council by video-conference from Juba.
The United States called for an international arms embargo.
UN ambassador Nikki Haley urged African leaders gathered for the summit to "consider seriously the accountability measures it pledged for those who refuse to pursue peace."
Haley singled out leaders in Uganda and Kenya to put pressure on Kiir, saying "they are key players in the success of a true peace process."
Kenyan President Uhuru Kenyatta on Saturday met UN Secretary-General Antonio Guterres on the sidelines of the summit to discuss the South Sudan conflict, according to a statement from the presidency.
The statement said Guterres had urged Kenya to return to the forefront of mediation after months spent occupied with domestic affairs due to a heated and drawn-out election.