United States Secretary of State Antony Blinken has spoken to leaders of rival armed forces in Sudan and urged an immediate cease-fire, the State Department said.

Blinken, "expressed his grave concern about the death and injury of so many Sudanese civilians due to the sustained, indiscriminate fighting," State Department spokesman Vedant Patel said.

A cease-fire would "permit the delivery of humanitarian assistance to those affected by the fighting, the reunification of Sudanese families, and allow the international community in Khartoum to make sure its presence is secure," Patel said in a statement.

Fierce clashes erupted over the weekend between forces loyal to Abdel Fattah al-Burhan, the head of Sudan's transitional governing Sovereign Council, and paramilitary Rapid Support Forces (RSF) head Mohamed Hamdan Dagalo, known as Hemedti, who is deputy head of the council.

At least 185 people have been killed and more than 1,800 injured.

When he spoke to the two men, Blinken "stressed the responsibility of the two generals to ensure the safety and wellbeing of civilians, diplomatic personnel, and humanitarian workers," Patel said

Following Blinken's call, Hemedti wrote on Twitter that he "reaffirmed our unwavering commitment to safeguarding innocent civilians in our areas of control."

He did not say whether he would stick to a possible cease-fire.

Al-Burhan has not spoken publicly since Saturday afternoon, when he accused the RSF of an attack and stressed that he had the situation under control.

G7 urges Sudan's warring parties to lay down arms

Foreign ministers of the G7 countries called on the warring parties to 'immediately' halt fighting

"We urge the parties to end hostilities immediately without pre-conditions. We call on all actors to renounce violence, return to negotiations, and take active steps to reduce tensions and ensure the safety of all civilians, including diplomatic and humanitarian personnel."

On Monday, United Nations (UN) envoy Volker Perthes said clashes have spread across Sudan.

"The two sides who are fighting are not giving the impression that they want mediation for a peace between them right away," Perthes told reporters by video link from Khartoum.

There are concerns the turmoil could spill across borders and destabilize the fragile region.

Egypt's el-Sissi denies interference in conflict

Egyptian President Abdel Fattah el-Sissi said late on Monday Egyptian troops in Sudan were merely there to conduct exercises with their Sudanese counterparts and not to support any of the warring parties.

After clashes erupted across Sudan, the RSF shared a video they said showed Egyptian troops who had "surrendered" to them in the northern town of Merowe.

El-Sissi also said Egypt was in regular contact with the Sudanese army and the RSF to encourage them to reach a cease-fire agreement.