Sudanese paramilitaries fought the regular army in Khartoum for control of a key armored corps base in the capital's south, witnesses said.
Fighters from Mohamed Hamdan Daglo's Rapid Support Forces (RSF) began their assault on the vast strategic compound on several fronts on Sunday.
Residents of Al-Shajara, the neighbourhood where the base is situated, reported "large losses on both sides" on the first day of the attack when the fighting was constant.
"This is the longest the fighting has lasted in Al-Shajara," said one, AFP reported.
The army led by General Abdel Fattah al-Burhan has put out several statements and videos saying it has repelled the RSF attacks.
But the paramilitaries said that since early Wednesday the RSF had "taken control of nearly the entire camp, with only a few minor areas still under contention".
Both sides post regular videos online showing what they say is their men inside the base, but it is not possible to independently verify which force holds which perimeter.
Each side has in the past claimed to have taken strongholds in Khartoum while they were in fact still fighting for them, as was the case with the army headquarters and the presidential palace.
The war between the rival generals and former allies erupted on April 15, and conservative estimates from the Armed Conflict Location & Event Data project are that nearly 5,000 people have been killed since then.
The bodies of many people have not been able to be recovered.
Rapid Support Forces commander Mohamed Hamdan Daglo, pictured with his paramilitary fighters at an undisclosed location
According to United Nations figures, in the four months since the fighting broke out more than 4.6 million people have had to flee their homes.
UN coordinator for humanitarian affairs Martin Griffiths late Tuesday again pleaded for both parties to stop fighting so aid could get through.
Among the areas badly in need are Kadugli, in South Kordofan state, where the main road into town has been blocked by the al-Hilu faction of the Sudan People's Liberation Movement-North (SPLM-N), the UN said.
The faction has been battling Sudan's army in the area.
"Due to the insecurity, aid workers travelling from out of the area are not able to reach the town," a UN report said, adding that humanitarian food supplies "will only last families until the end of this month".
In a joint appeal on August 15, the heads of 20 global organisations had warned that "more than six million Sudanese people are one step away from famine".
