KHARTOUM - The U.N. on Thursday urged countries with influence in Africa to help end the conflict in Sudan after reported progress in truce talks between the army and the rival paramilitary Rapid Support Forces.

Clashes rocked Halfaya, an entry point to the capital, early on Thursday as residents heard warplanes circling over Khartoum and its adjoining sister cities of Bahri and Omdurman, but the fighting appeared calmer than on Wednesday.

In public neither side has shown it is ready to offer concessions to end the conflict that erupted suddenly last month, threatening to pitch Sudan into a civil war, killing hundreds of people and triggering a humanitarian crisis.

Army general Yassir al-Atta was quoted on Thursday saying the talks should aim at removing the Rapid Support Forces (RSF) from Khartoum, merging its fighters into the regular military and putting its leaders on trial.

"Any dialogue outside those points is simply delaying the war to another time," he told Asharq al-Awsat newspaper, adding the army had beaten back RSF forces at one key Khartoum location.

The RSF on Wednesday said it held nearly all of Khartoum and accused the army of "unrelenting violations". Reuters could not independently verify their accounts.

The talks in the Saudi port of Jeddah represent the most serious effort yet to stop the fighting and U.S. mediators said on Wednesday they were "cautiously optimistic".

Previous ceasefire agreements have been repeatedly violated, leaving civilians to navigate a terrifying landscape of chaos and bombardment with failing power and water, little food and a collapsing health system.

On Thursday the army warned it would target what it said were RSF fighters in civilian clothes using motorcycles, and warned ordinary residents of the capital not to use the vehicles.

JEDDAH TALKS

The World Health Organization has said that more than 600 people have been killed in Sudan and more than 5,000 injured in the fighting. The Health Ministry said at least 450 people were killed in the western Darfur region.

Many have fled Khartoum and Darfur, uprooting 700,000 people inside the country and sending 150,000 as refugees into neighbouring states according to U.N. figures.

The Jeddah talks are focused on securing a ceasefire and guarantees of safe access for humanitarian assistance in a country where 16 million people already depended on aid before fighting began.

U.N. Sudan envoy Volker Turk said in Geneva that both sides had trampled international humanitarian law and he urged "all states with influence in the region to encourage, by all possible means, the resolution of this crisis".

Western countries condemned abuses by both sides at a human rights meeting in Geneva, but Sudan's envoy there said the conflict was "an internal affair".

Many foreign countries have evacuated their nationals from Sudan, including through an organised week-long airlift and naval operation that took out thousands.

However, thousands of citizens of impoverished Yemen, which is itself immersed in conflict, remain stranded in Sudan across the Red Sea from their homeland.

"We were surprised with the slow procedures to evacuate the displaced to Yemen," said Abdel Hakeem Ali, a Yemeni national in Port Sudan who had fled from Khartoum in a group that included 10 children.

Saudi Arabia said it would extend the residence permits of Sudanese pilgrims visiting Islam's holy sites in the kingdom.

(Reporting by Nafisa Eltahir in Cairo, Aziz Yaakoubi in Riyadh, Hatem Maher in Dubai and Emma Farge and Gabrielle Tetrault-Farber in Geneva; Writing by Angus McDowall; Editing by Andrew Heavens)