“It’s a very fluid situation so it’s very difficult to say where the balance is shifting to,” Volker Perthes said on Monday of the violence between the army and paramilitary forces led by rival generals.

Speaking to reporters in New York via video, he also said that the warring sides were “not giving the impression that they want mediation for a peace between them right away”.

The sudden outbreak of violence over the weekend between the nation’s two top generals, each backed by tens of thousands of heavily armed fighters, trapped millions of people in their homes or wherever they could find shelter, with supplies running low in many areas.

The power struggle pits General Abdel Fattah al-Burhan, the commander of the armed forces, against General Mohamed Hamdan Dagalo, the head of the Rapid Support Forces (RSF), a paramilitary group. The former allies jointly orchestrated an October 2021 military coup.

The violence has raised the spectre of civil war just as Sudanese were trying to revive the drive for a democratic, civilian government after decades of military rule.

Calls for truce

On Monday, UN Secretary-General Antonio Guterres again called on Sudan’s warring parties to “immediately cease hostilities”. He warned that further escalation “could be devastating for the country and the region”.

The White House on Monday also called for an immediate ceasefire to fighting in Sudan, adding: “We deplore the escalating violence out of Khartoum and elsewhere in Sudan. We call for an immediate ceasefire without conditions.”

Al Jazeera’s James Bays, reporting from the UN, said various international players are being relied on to broker a ceasefire.

“[The UN envoy to Sudan] believes pressure from others is important. The African Union, regional grouping IGAD, Arab League, all of these bodies are talking with various players and in particular with the two generals, trying to get a ceasefire in place,” Bays said.

“There’s talk of mediation missions … making their way as delegations to try to speak to the generals to try to get that ceasefire.

“The problem with that – airspace is closed, borders are closed and it’s simply too dangerous for them to travel at this stage. Diplomatic efforts are ongoing, but they’re not bearing much fruit this time and clearly that’s deeply concerning for the people of Sudan.”

Meanwhile, Sudan’s army has declared the RSF a rebel group and ordered its dissolution on Monday.

As the fighting showed no sign of abating, Dagalo took to Twitter to call for the international community to intervene against al-Burhan, branding him a “radical Islamist who is bombing civilians from the air”.

In a rare statement since the fighting flared, al-Burhan told Al Jazeera on Saturday that he was “surprised by Rapid Support Forces attacking his home” and that what was happening “should prevent the formation of forces outside the army”.

Sudan’s doctors’ union warned the fighting had “heavily damaged” multiple hospitals in Khartoum and other cities, with some rendered completely “out of service”.

The World Health Organization had already warned that several of Khartoum’s nine hospitals receiving injured civilians “have run out of blood, transfusion equipment, intravenous fluids and other vital supplies”.

Under lockdown

The violence has forced terrified people to shelter in their homes with fears of a prolonged conflict that could plunge Sudan into deeper chaos, dashing hopes for a return to civilian rule disrupted by the 2021 coup that al-Burhan and Dagalo orchestrated.

Al Jazeera’s Hiba Morgan, reporting from Khartoum, has said that she and her colleagues have not been able to go outside for the past three days as “it’s not clear which forces are in control of which locations exactly.

“Both sides are very hard to negotiate. We’re talking about soldiers here, people on the ground – not senior commanders. Even if we do manage to talk to their leadership to understand what’s going on from their perspective, those on the ground don’t necessarily agree with us moving around, so we have been under lockdown for the past three days,” Morgan said.

“It’s not only here where we are that we are facing lockdown, other parts of the capital as well – residents say that they can’t leave their homes because of the insecurity that they’re facing.”

The RSF was created under Sudan’s former President Omar al-Bashir in 2013.

It emerged from the so-called Janjaweed militia that his government unleashed against non-Arab ethnic minorities in Darfur a decade earlier, drawing accusations of war crimes.

The fighting broke out after bitter disagreements between al-Burhan and Dagalo over the planned integration of the RSF into the regular army – a key condition for a final deal aimed at ending a crisis since the 2021 coup.

The two sides accuse each other of starting the fighting, and both claim to be in control of key sites, including the airport and the presidential palace – none of which could be independently verified.