By Aidan Lewis and Tom Perry
CAIRO (Reuters) - Sudan's warring factions are locked in a conflict that two weeks of fighting shows neither can easily win, raising the spectre of a drawn-out war between an agile paramilitary force and the better-equipped army that could destabilise a fragile region.
Even with hundreds of people killed and the capital Khartoum turned into a war zone, there has been little sign of compromise between army commander Abdul-Fattah al-Burhan and Mohamed Hamdan Dagalo, head of the paramilitary Rapid Support Forces (RSF), commonly known as Hemedti.
Foreign mediators have struggled to arrest the slide to war: a series of ceasefires brokered by the United States and others have been undermined by shelling and air strikes in Khartoum and conflict elsewhere, including the Darfur region in the west.
Giving a faint flicker of a hope, U.N. Sudan special envoy Volker Perthes said on Saturday he saw signs of more openness to negotiations, but renewed fighting was heard in the capital.
Hemedti and Burhan have both excluded the idea of negotiating with each other in public comments since the fighting began.
An aide to Hemedti did not respond to questions from Reuters about whether he was ready to negotiate or hold peace talks. Hemedti on April 20 said he would not sit with Burhan, who he called a "criminal".
An aide to Burhan, asked the same questions, referred Reuters to Burhan's remarks to U.S based al-Hurra TV this week, where he said he cannot sit down with "the leader of the rebellion", a reference to Hemedti.
The stakes couldn't be higher both for Sudan and seven neighouring states where stability may be jolted by conflict in a country with a history of civil strife, including the decades-long war that ended with southern secession in 2011.
Despite its air force and tanks, the army has so far been unable to dislodge RSF fighters spread out through Khartoum, which has been spared violence in Sudan's past civil wars.
It spells a drawn-out fight for the capital on the Nile, where the army said on Thursday RSF fighters were being defeated but a Western diplomat assessed the RSF to have the upper hand.
Many civilians have fled the capital for safer areas. Residents have described a rapid breakdown as gangs and looters maraud in empty streets, neighbourhoods are rocked by air strikes and shelling, and food and fuel run low.
Even if the army can prevail in Khartoum, analysts worry the stage is being set for a return to the usual pattern of Sudan's internal wars -- pitting the nation's military run by a powerful elite in the capital against those hailing from the regions angry at being marginalised, such as Darfur, the region where Hemedti and his RSF first emerged as a fighting force.
A senior regional diplomat described the situation as "terrifying".
"We will have a lot of fragmentation," the diplomat said, expressing concern about renewed conflict between the centre in Khartoum and peripheral regions in the country of 46 million.
NO GOOD SCENARIOS
Tensions had been simmering for months between Hemedti and Burhan over how the RSF - estimated at 100,000 - should be integrated into the Sudanese army under an internationally-backed framework deal for civilian government, and over the chain of command in the lead up to elections.
A former Darfur militia leader, Hemedti had grown powerful as enforcer for veteran autocrat Omar al-Bashir, and rich thanks to the gold trade. He served as Burhan's deputy on Sudan's ruling council after Bashir's overthrow.
Hemedti insisted the RSF's integration should be stretched over 10 years, in line with details of a framework transition plan, sources familiar with the talks have said, while the army wanted a much shorter time frame.
Underlining the difficult outlook for peacemaking, mediators aimed at getting a ceasefire in place and to "stabilise the situation in that way, rather than going for some kind of big bang peace deal", the Western diplomat said.
"What are they going to talk about that wasn't on the table before the conflict started?" said the diplomat, adding that neither side could win a decisive military victory or control of all Sudan's territory.
Ahmed Soliman of Chatham House, a think-tank in London, said he foresaw "very bad scenarios either way with a limited likelihood of a short-term resolution that would halt the fighting permanently".
"You have the RSF as a much more mobile force - very battle hardened using guerrilla tactics in urban areas - while the Sudanese armed forces have air power, tanks and better logistics," he said.
The army appeared to be trying to hunt down Hemedti in the hope of dealing a killer blow to the RSF, he said.
"Over time they might be able to push the RSF out of Khartoum ... if that scenario plays out there would be increased contestation in the Darfur region, the effects of which we are already starting to see," he said.
The violence risks burying once and for all a political process that was supposed to establish democracy in Sudan after Bashir and his Islamist political base were ousted in 2019 following three decades in charge.
Sudanese who have struggled for civilian rule worry the clock is being turned back, and that the mayhem may allow the military to entrench its grip on power alongside a comeback by members of Bashir's administration.
Echoing army statements, a Sudanese government official described the conflict as between a legitimate army and a rebel militia that must surrender and with which there can be no negotiation.
The RSF, which has bases across Sudan, has meanwhile depicted the army as "extremists", an apparent reference to the influence Hemedti says Islamists wield in the military.
Analysts believe foreign powers with sway over the sides - notably Egypt which has close ties to the army and Gulf Arab states seen to have influence over Hemedti - could yet put more pressure on them to deescalate.
"The chances of a permanent ceasefire will increase if both sides can be brought to realise they have nothing to gain from this conflict," said Willow Berridge, a historian, adding that regional powers could play a role convincing them.
(Additional reporting by Samia Nakhoul, Tala Ramadan and Nafisa Eltahir; Writing by Tom Perry; Editing by William Maclean)