Armed Clashes in Sudan
On 15 April 2023, armed clashes between the Rapid Support Forces and the regular army in the Sudanese capital Khartoum were reported. Later, the fighting between the military forces spread to other Sudanese regions.

Sudan’s RSF Mercenaries Come From African Countries, Not From Ukraine, Sudanese Army States

CAIRO (Sputnik) – Mercenaries fighting on the side of the paramilitary Rapid Support Forces (RSF) of Sudan are from the countries of the region, not from Ukraine, the official spokesman for the Sudanese army, Nabil Abdallah, told Sputnik.
Sputnik
Earlier in August, Mali severed diplomatic ties with Ukraine over Kiev's support to Malian Tuareg rebels behind an attack in late July that killed dozens of Malian soldiers and Russia's Wagner group troops.

"There is no Ukrainian presence in Sudan at all. All these conversations have nothing to do with reality," Abdallah said in response to a question as to whether there is any information about Ukrainians' participation in the conflict in Sudan in the light of recent statements about their activity in a number of African countries.

A large number of foreign mercenaries are indeed fighting on the side of the RSF, but most of them come from Chad, Niger, Mali, and South Sudan, Abdullah said.
Since April 2023, violent fighting has been going on in Sudan between the RSF, under the command of Mohamed Hamdan Dagalo, and the regular army.