Kenya was condemned by Sudan and critics at home as "criminally irresponsible" on Wednesday for hosting Sudanese paramilitary rebels who are planning to declare a parallel government.
The paramilitary Rapid Support Forces, at war with the Sudanese army for nearly two years, are preparing to proclaim a government in territories under their control at an event in Nairobi on Friday, RSF sources told AFP.
Sudan's foreign ministry, loyal to army chief Abdel Fattah al-Burhan, criticised Kenya for allowing the event.
The move "promotes the dismembering of African states, violates their sovereignty, and interferes in their internal affairs," it said in a statement.
Kenyan President William Ruto also faced widespread criticism at home.
"What Ruto is doing is a reckless abandonment of the traditional caution and dignified approach to Kenyan diplomacy," Mukhisa Kituyi, a Kenyan politician and former secretary-general of United Nations Trade and Development, told AFP.
He is "trying to legitimise a criminal gang that has been dismembering people," he added, calling the move "criminally irresponsible".
Ruto's government did not respond to a request to comment.
Since April 2023, the war between the army and RSF has killed tens of thousands of people, uprooted more than 12 million and created the world's largest hunger and displacement crises.
The African Union in a statement published on Wednesday voiced "deep concern over the continued escalation of the conflict, between the two warring parties, particularly the non-stop perpetration of war crimes and crimes against humanity".
- Sudan ethnic violence -
The conflict has torn the country apart, with the army controlling eastern and northern Sudan while the RSF commands nearly all of the western Darfur region and swathes of the south.
The army has recently reclaimed key cities and nearly all of the capital, Khartoum.
The RSF's decision to sign a charter with allied political factions is seen as an attempt to consolidate its hold on Darfur, effectively splitting the nation.
The paramilitaries are notorious for ethnic-based mass executions, sexual violence and human rights violations in their territories.
In January, the United States determined they had committed genocide in Darfur, sanctioning RSF commander Mohamed Hamdan Daglo -- as well as army chief Burhan -- for war crimes.
Sudan's loyalist foreign ministry accused Kenya of "endorsing (the RSF's) atrocities and being complicit in them" by giving the RSF a platform.
The event, initially scheduled for Tuesday at Nairobi's state-owned Kenyatta International Convention Centre, was postponed to Friday.
Daglo, who has remained out of sight for most of the war, has arrived in Kenya and is expected to attend, organisers told AFP.
Kenya has long hosted regional peace deals, including Sudan's Comprehensive Peace Agreement 20 years ago to end another civil war.
But a lawyer for Refugees International, a campaign group, said the latest move "shatters" the image Kenya likes to project of itself.
Abdullahi Boru Halakhe described the decision to host the RSF as "genocide-washing".
"This is bottom-of-the-barrel diplomatic stuff that you cannot come back from," he told AFP.