KHARTOUM: Gunfire ripped through residential neighbourhoods of Sudan's capital Khartoum at the start of the Muslim holiday of Eid al Fitr on Friday, after the army deployed on foot for the first time in its almost week-long fight with a paramilitary force.

Soldiers and gunmen from the paramilitary Rapid Support Forces (RSF) shot at each other in the north, west and centre of the city, including during the call for special early morning Eid prayers, witnesses said.

The unabated fighting has killed hundreds. In the absence of a ceasefire, foreign nations including the United States have been unable to evacuate their citizens from Sudan.

International efforts to broker a temporary truce over the three day holiday and allow civilians to reach safety have so far failed.

Instead, the army appeared to enter a new phase of battle on the ground, fighting the RSF in residential neighbourhoods, after having stuck largely to air strikes across the capital, with fiercer clashes in central Khartoum.

Army chief General Abdel Fattah al-Burhan said on Thursday he saw "no other option but the military solution" to the power struggle with the paramilitary force that erupted into violence last weekend.

The conflict between two previously allied leaders of the ruling military junta, army chief Burhan and RSF leader General Mohamed Hamdan Dagalo, also known as Hemedti, risks drawing in Sudan's neighbours and could play into regional competition between Russia and the United States.

The thud of heavy weaponry could be heard across Khartoum and its Nile sister cities, together one of Africa's biggest urban areas. Army troops brandishing semi-automatic weapons were greeted by cheers on one street, footage released by the military on Friday showed.

Reuters verified the location of the video, in the north of the city, but could not immediately verify when it was filmed.

The World Health Organization said at least 413 people have already been killed and thousands injured in the conflict, which has tipped Sudan into a humanitarian disaster, with hospitals under attack and up to 20,000 people fleeing into neighbouring Chad.

Thousands more Sudanese fled Khartoum on Friday, moving south to Al Gezira state, or north to River Nile state, with some seeking to go onward to Egypt.

Even before the conflict, about a quarter of Sudan's people were facing acute hunger, with children especially affected. The U.N. World Food Programme halted its Sudan operation, one of its largest, on Saturday after three of its workers were killed.

The violence was triggered by disagreement over an internationally backed plan to form a new civilian government four years after the fall of autocrat Omar al-Bashir to mass protests, and two years after a military coup.

Both sides accuse the other of thwarting the transition.

DARFUR CASUALTIES

The fighting on Friday undermined efforts by U.N. Secretary General Antonio Guterres to win a truce, despite a flurry of phone calls to Burhan from the U.S., Qatari, and Saudi foreign ministers, the Turkish president, and other world leaders on Thursday.

The RSF condemned the military for what it said was new assaults.

"At this moment, when citizens are preparing to receive the first day of Eid al-Fitr, the neighbourhoods of Khartoum are waking up to the bombings of aircrafts and heavy artillery in a sweeping attack that is directly targeting residential neighbourhoods," the RSF said early on Friday.

Beyond the capital, the two sides are fighting in the western region of Darfur, where a partial peace deal was signed in 2020 in a long-running conflict that led to international war crimes charges against Bashir.

In El Fasher in North Darfur, a maternity hospital repurposed to treat casualties from fighting was overwhelmed and rapidly running out of supplies, said Cyrus Paye, coordinator for aid group MSF which supports the facility. All other hospitals in the city were closed.

Most of the 279 wounded patients the hospital received since Saturday were civilians hit by stray bullets, many of them children, and 44 have died, he said.

Another doctors' group said at least 26 people were killed and 33 were wounded El-Obeid city, also west of Khartoum, on Thursday. Witnesses there described clashes and widespread looting.

Guterres, speaking to reporters after meeting virtually with the heads of the African Union, the Arab League and other organisations on Thursday, said trapped civilians should be allowed to seek medical treatment, food and other supplies.

Burhan told Al Jazeera he would support a truce on condition it allowed citizens to move freely, which he said the RSF had prevented.