Here are some facts about Sudan's army and the Rapid Support Forces (RSF) paramilitary group which have been fighting each other for a year, devastating their country, reigniting ethnically-targeted killings in Darfur and displacing millions.
The factions, uneasy partners in the toppling of President Omar Hassan al-Bashir in 2019 and the overthrow of a civilian-led government in 2021, clashed as they competed to protect their interests in a planned political transition.
THE ARMY
* Sudan's armed forces, commanded by General Abdel Fattah al-Burhan, had the advantage on paper at the start of the war because of their higher troop numbers, their heavy weapons and fighter jets.
* As an institution, they have been at or close to the centre of power in Sudan for decades. Burhan - born around 1960 in a village north of Khartoum neighbouring Bashir's home - has spent his whole career at the centre of that institution.
* However, the armed forces have often outsourced fighting to allied groups in various regions of Sudan - including the militias that developed into the RSF in Darfur - while building up extensive economic interests.
* Under Bashir, Burhan served in Darfur, where the government fought to put down a rebellion in violence that had displaced an estimated 2 million people and left 300,000 dead by 2008. He also developed ties in the Gulf, helping supply soldiers to a Saudi-led military coalition fighting in Yemen.
* Burhan said he was among the military figures who told Bashir that he needed to step down, quickly emerging afterwards as Sudan's effective leader.
* In the first days of the war, the army lost ground to the RSF's more nimble units across the capital, and then later in Darfur and el-Gezira state south of Khartoum.
* Early this year it has regained some footing, particularly in Omdurman, across the Nile from Khartoum - supported, sources say, by Iranian-made drones. It has also received support from foreign powers including neighbouring Egypt and largely holds north and eastern Sudan including Port Sudan on the Red Sea.
* Residents have accused the army of killing civilians in indiscriminate shelling and air strikes in parts of Khartoum and other areas held by the RSF. The army had largely denied the accusations.
THE RSF
* The RSF is commanded by the wealthy, one-time militia leader General Mohamed Hamdan Dagalo, who is known as Hemedti. Analysts estimated the force numbered about 100,000 before the war started, with bases and deployments across the country.
* Hemedti, a school dropout now in his late 40s, began as a camel trader in Darfur. According to Muhammad Saad, a former assistant, he first took up arms after men attacked his trade convoy, killed about 60 people from his extended family and stole his livestock.
* His fighting skills were honed when his loyalists and other irregulars allied with the government to help quash the rebellion in Darfur in a campaign that escalated in 2003. The militia forces became known as the Janjaweed, a term loosely derived from the Arabic for 'devils on horseback' that reflected their fearsome reputation.
* International Criminal Court prosecutors accused government officials and Janjaweed leaders - without naming Hemedti - of genocide and other atrocities.
* Over time the RSF grew and in 2017 won official recognition as a military force, with Bashir's support. In tandem, the business interests of Hemedti have expanded in gold mining, infrastructure, livestock and other areas.
* His forces have proved wily adversaries to the army, capturing some of their bases and melting away into residential areas where heavy armour and conventional military tactics lose advantage.
* Residents, rights groups and U.N. experts have accused the RSF and allied militias of perpetrating ethnically-targetted attacks in Darfur, accusations denied by the RSF.
* Hemedti's most important ally has been the United Arab Emirates, Sudanese sources, analysts and diplomats say. The UAE has denied reports of sending arms shipments to the RSF.
