Inside Sudan's El Fasher, a city under siege amid a civil war

Since May, North Darfur's capital, El Fasher, has been under siege.

"El Fasher was a city of refuge, a city of refugees and home to the displaced," Yasin, a former resident, told to ABC News over the phone. "It was a shelter; people came from different parts of Darfur. But soon it turned into a city of misery and destruction."

Fighting between the Sudanese Armed Forces (SAF) and the powerful Rapid Support Forces (RSF) paramilitary group began to intensify around the city as a bitter battle for its control – the last in Darfur in the hands of the Sudanese army – began to ensue.

Trapped in the midst of the crossfire were an estimated 800,000 civilians, according to the United Nations. Yasin -- who has since fled to a neighboring town after a long and grueling journey -- was one of them.

"We endured over 45 days of attack and never-ending shelling," he told ABC News. They shelled out neighbourhood. They shelled areas around our neighbourhood. It became a life of misery … it is very easy to die in El Fasher city."

Last month, the months-long siege on the North Darfur capital intensified, with the RSF launching a new offensive.

"It was the most scariest thing we ever experienced, only by a whisker we escaped," Fatima, another former resident, told ABC News over the phone. She said she sought refuge in El Fasher with her family and is now on the move once again, after fleeing to a nearby town at the onset of the RSF's new assault last month.

"Adding to the pain is all we have lost. We have lost so much; we have lost everything we have worked for," she said. "We no longer have a home, our children no longer can go to school. I fear for them every day. We lost all our dreams and our hopes. Just like that we are refugees, our lives is just about trying to survive the day."

"It is the biggest heartbreak that we are suffering everyday, oh my dear Sudan," she said.

El Fasher -- once a key humanitarian hub and safe-haven to hundreds of thousands who fled from other parts of Sudan -- is now on the brink of collapse, with hospitals, markets, schools, targeted, according to international observers. ABC News has viewed video sent from El Fasher that appeared to show the graphic aftermath of shelling, including that of displacement camps.

Analysis from the Yale School of Public Health's Humanitarian Research Lab found "high-tempo, intense" combat activity is ongoing El Fasher, the city is a "free-fire" zone for RSF and SAF forces. SAF and RSF artillery strikes, SAF air strikes and helicopter gunship activity have all been detected. The report warns that the tempo of combat is "likely to effectively reduce what is left of El Fasher to rubble."

The siege continues after famine was confirmed in Sudan's North Darfur: The Famine Review Committee found El Fasher's Zamzam refugee camp -- which houses hundreds of thousands of displaced persons -- has passed famine thresholds.

The toll on civilians immense. The U.N. said it has documented increasing civilian casualties as a result of shelling and airstrikes by warring parties, as well as incidents of summary executions, sexual and gender-based violence and abductions. Many remain trapped in the city, the U.N. said, unable to meet the high costs and payments to leave or manoeuvre the dangerous routes out of the city as fighting continues.

"From bitter past experience, if El Fasher falls, we believe there is a high risk of ethnically targeted violations and abuses including summary executions and sexual violence by the Rapid Support Forces and allied militia," said U.N. High Commissioner for Human Rights Chief Volker Türk. "The fighting must stop at once. Enough is enough."

The RSF on Tuesday claimed what they say is a "extraordinary victory" in North Darfur, saying soldiers quashed an advance by "enemy factions" toward El Fasher following an "Intense clash" near Al-Malha, just outside the city. The RSF claim to have inflicted "staggering losses," killing "450 enemy combatants" and capturing over 100 vehicles as well as seizing weapons and ammunition. ABC News is unable to independently verify these claims.

In a statement sent to ABC News, a State Department spokesperson said: "The United States condemns in the strongest possible terms the Rapid Support Forces' (RSF) escalation of attacks on El Fasher as well as the shelling of nearby displacement camps."

The statement added, "We are equally concerned that the Sudanese Armed Forces (SAF) have responded with increased widespread aerial bombardments of the area, which only worsens the situation for the Sudanese people trapped in the city."

"We urge the RSF to stop its assault, including its targeting of schools, hospitals, and markets, and to take steps to protect civilians and live up to the civilian protection commitments it made in Switzerland last month and in Jeddah in May 2023," a State Department spokesperson said.

Sudan was plunged into war in April 2023 following months of long-simmering tensions between Sudanese Army Chief Burhan and RSF paramilitary group commander Dagallo -- also known as Hemedti -- over a planned transition to civilian rule. Fighting broke out in Sudan's capital Khartoum, before spreading throughout the country as a battle ensued between warring generals for control of the resource-rich northeast African nation, allied militias joining the fight.

The conflict has precipitated one of the world's 'worst humanitarian crises' in recent history, at least one quarter of Sudan's population forced to flee from their homes. As the war enters its 18th month at least 20,000 people have been killed according to the United Nations.

Local groups however warn the true toll is likely much higher.

"Sudan is facing very serious challenges," said Al Burhan in an address at the United Nations General Assembly last Thursday, a speech that coincided with the SAF's largest offensive in months as the army sought to regain ground in the capital Khartoum.

Speaking to reporters on the sidelines of UNGA in New York, the army chief -- and de facto head of state -- said he had evidence the United Arab Emirates (UAE) was providing support in the form of arms to the powerful RSF paramilitary group.

In a statement sent to ABC News, the UAE government denied involvement in the war in Sudan: "In regard to the continued allegations from the Sudanese Armed Forces and their representatives in government, we have made absolutely clear to the United Nations Security Council and to all other international partners, that the UAE is not providing any support or supplies to the Rapid Support Forces (RSF), or to any of the warring parties in Sudan," the UAE government said.

"Today, a violent history is repeating itself," said U.S. President Joe Biden in a September statement on the war in Sudan, describing the situation in El Fasher as a "siege [that] has become a full-on assault in recent days."

"I call on the belligerents responsible for Sudanese suffering -- the Sudanese Armed Forces and the Rapid Support Forces -- to pull back their forces, facilitate unhindered humanitarian access, and re-engage in negotiations to end this war," he said.