UNITED NATIONS - Aid officials are extremely concerned about an escalating Sudan war following reports of atrocities in the takeover of Zamzam displacement camp in North Darfur by armed groups, UN humanitarians said on Wednesday.

The UN Office for the Coordination of Humanitarian Affairs (OCHA) said it is gravely concerned by the humanitarian situation in and around El Fasher, the capital of North Darfur State, just 15 km north of the vast and famine-scarred camp.

"Local partners have provided deeply disturbing reports of atrocities following the reported takeover of Zamzam displacement camp by armed groups," OCHA said. "Civilians, including humanitarian workers, are reportedly being prevented from leaving, and survivors have spoken of targeted killings, sexual violence and the burning of homes."

When asked about the paramilitary Rapid Support Forces (RSF) setting up a parallel government to the one in Sudan's capital of Khartoum, Stephanie Tremblay, associate spokeswoman for the UN secretary-general, said that it would not bring Sudan any closer to a resolution of the conflict, which can only be achieved through meaningful, inclusive dialogue.

"As an international community, we must find ways to help the Sudanese people bring this unspeakable catastrophe to an end and establish acceptable transitional arrangements," Tremblay said.

Earlier in the week, it was reported about 400,000 of the estimated 500,000 people living in Zamzam camp fled with the onslaught of armed groups believed affiliated with the RFS militia.

OCHA said local sources reported people moving to areas including Jebel Marra and Tawila, west and southwest, respectively, of El Fasher amid a highly volatile security situation and continuing attacks.

"Access constraints, a critical fuel shortage and a volatile security environment are severely disrupting humanitarian operations in El Fasher," OCHA said. "Health services and water treatment have been particularly affected."

Tremblay said that in Khartoum State, drones on Monday attacked power infrastructure, leaving large parts of the districts of Um Badda, Karrari and Omdurman without electricity or clean water. Partners warn that most water plants are no longer operational, and a significant water station serving the cities of Atbara and Ad Damar now requires emergency diesel support to function.

On Tuesday, the Sudan war marked the second anniversary of the RSF attacks in Khartoum, igniting the war that has taken the lives of nearly 30,000 people, forced about 13 million from their homes, 4 million of those to neighboring countries, and left about half of the 50 million population hungry.

"Once again, OCHA calls on all parties to the conflict to protect civilians and facilitate humanitarian access," the office said. "We also urge increased international support to ensure essential services and humanitarian assistance to the most vulnerable people in Sudan continue."