A witness in west Khartoum reported army air strikes on paramilitary forces, as brutal urban warfare continued in Sudan's densely-populated capital.

More than 750 people have been killed and hundreds of thousands displaced since fighting erupted on April 15 between army chief Abdel Fattah al-Burhan and his deputy turned rival Mohamed Hamdan Daglo, who commands the paramilitary Rapid Support Forces.

Over half a million people have fled Khartoum alone, according to the UN, with hospitals there shelled and rampant looting reported as residents suffer chronic shortages of food, electricity and medicine.

Representatives of both generals have been in the Saudi city of Jeddah for a week, for talks intended "to protect Sudan from any escalation that will lead to a humanitarian catastrophe", a Saudi diplomat said on condition of anonymity.

The diplomat also said Burhan had been invited to attend the Arab League summit planned to take place in Jeddah on May 19 but it was unclear who would be representing Sudan.

"We didn't receive the name of the delegations, but we're really expecting Sudan will be present in," the diplomat said.

- 'Houses shaking' -

Envoys in Jeddah agreed on Thursday to "affirm our commitment to ensure that civilians are protected".

However the deal, dubbed the Jeddah Declaration, did not amount to a truce and the situation on the ground appeared unchanged.

In the capital's twin city of Omdurman, "houses are shaking from the force of explosions", a witness told AFP Saturday, reporting armed clashes.

Thursday's deal commits both sides to let in badly needed humanitarian assistance and also calls for the restoration of water, electricity and other basic services.

The shortages have been felt even in areas removed from the fighting.

According to Moussa Hassan, a resident of Kassala, "prices have skyrocketed" in the city 400 kilometres (250 miles) east of the capital, as tens of thousands fleeing Khartoum transit through.

"Local authorities have declared a state of emergency" in a bid to ration essentials and prevent price gouging, Hassan told AFP.

Sudan launched on Saturday a plea for humanitarian assistance from the international community, including the United Nations, the African Union, and other regional organisations.

The government committed to "dedicating the port and airports of Port Sudan" on the Red Sea, Dongola airport in the country's north and Wadi Seidna air base near the capital "to receive aid".

Civilians and aid groups have repeatedly pleaded for humanitarian corridors to secure vital assistance, as aid agencies have been systematically looted and at least 18 humanitarian workers killed.

UN Secretary General Antonio Guterres expressed hopes the Jeddah deal would "ensure that the relief operation can scale up swiftly and safely to meet the needs of millions of people in Sudan", where a third of the population relied on aid even before the current conflict.

Guterres also reiterated "his call for an immediate ceasefire and expanded discussions to achieve a permanent cessation of hostilities", in a Friday statement.

- 'Quite far apart' -

An RSF statement Friday said the group had signed the Jeddah agreement despite their "full knowledge" that the army "will not heed the suffering of our people".

Hopes for a ceasefire remain dim after multiple truces were violated in past weeks.

US officials have described the talks as difficult, with one saying the two sides were "quite far apart".

But the Saudi diplomat said there had been "a positive response" and there was "a good spirit from the two parties".

The diplomat nonetheless declined to comment on whether the two camps met directly.

For Aly Verjee, Sudan researcher at Sweden's University of Gothenburg, "it is not surprising that the Jeddah Declaration is weak".

"Initial agreements usually are," he told AFP. "The mediators are still in the public honeymoon phase... this explains the claims of optimism, even when there is little evidence to justify such views."

On the ground, both sides have continued to trade gunfire and accusations, each blaming the other for attacking infrastructure and civilians.

"We keep hearing that there will be a truce, but then you go out in the street and there are bullets everywhere," Sudanese citizen Wahag Gafar told AFP after a gruelling journey to the border with Egypt, where over 60,000 have fled the fighting.

Almost 200,000 people have escaped Sudan, in addition to hundreds of thousands who have been displaced inside the country, the UN said Friday.

The exodus has seen Sudanese rush to neighbouring Chad, South Sudan and Ethiopia, where the UN refugee agency warned that its operations were "already significantly underfunded".

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