The two rival generals fighting in Sudan agreed to a seven-day truce starting on Thursday and will name representatives to peace talks, according to the foreign ministry of South Sudan, which has been working with other neighboring countries to negotiate an end to a conflict that has sent more than 100,000 refugees pouring across their borders in a few weeks.

There was no immediate public confirmation, however, that an agreement had been reached from either side in the conflict between the Sudanese Army, led by Gen. Abdel Fattah al-Burhan, and the paramilitary Rapid Support Forces, led by Lt. Gen. Mohamed Hamdan. And no date has been set yet for negotiations to begin, South Sudan’s foreign ministry added in a statement.

The United Nations has also been pressing for peace talks, and a spokesman, Farhan Haq, was cautious about South Sudan’s statement on Tuesday. Mr. Haq, deputy spokesman for the U.N. secretary general, said at a briefing: “We would certainly welcome any lasting meaningful truce. First, of course, we will have to see whether this is accepted by all the parties and whether it is implemented by the forces on the ground.”

The fighting has persisted despite previous cease-fires and threatens to undermine regional stability. More than 300,000 people have been internally displaced, in addition to the more than 100,000 who have fled, mostly into Chad, South Sudan, Egypt, Ethiopia and the Central African Republic, according to figures released by United Nations agencies on Tuesday.

The U.N. refugee agency also warned that more than 800,000 people could try to escape Sudan by the end of this year to the seven nations bordering the northeastern African country — many of them already reeling from a multitude of their own economic, political and refugee crises.

More than 500 people have died and over 4,000 have been injured in the latest conflict in Sudan, according to the World Health Organization.

Neighboring South Sudan was one of the first countries to offer to arbitrate between the two warring sides, with President Salva Kiir offering to host along with his Egyptian counterpart, President Abdel Fattah el-Sisi. South Sudan is part of the Intergovernmental Authority on Development, an eight-nation regional bloc that includes Sudan. And Sudanese political factions have in the past convened in South Sudan for talks on sharing power and ending the longstanding conflict in Darfur and other regions.

On Tuesday, the regional bloc said in a statement that it was “particularly happy” to see that both General al-Burhan and General Hamdan “are persuaded that dialogue is the best and only option to address grievances and not war.”

The outbreak of violence in Sudan has dashed whatever hopes residents had of achieving a transition to civilian democratic rule, which was scuttled by a military coup in 2021.

On Tuesday morning, residents in parts of the capital, Khartoum, reported intense clashes and heavy shelling throughout the night before. Many residents are without electricity and worried about dwindling food and water. Given the deteriorating situation, the United Nations said it was preparing for a mass exodus from Sudan, a nation of more than 45 million people that was already facing dire humanitarian crises before the latest fighting.

“We hope it doesn’t come to that,” Filippo Grandi, the high commissioner for the U.N. refugee agency, said in a statement, “but if violence doesn’t stop, we will see more people forced to flee Sudan seeking safety.”

More than 334,000 people were also internally displaced in 14 of Sudan’s 18 states, the International Organization for Migration said on Tuesday.

The U.N. predictions that more than 800,000 could flee over the rest of this year were published after consultations with the governments of the seven nations surrounding Sudan — the Central African Republic, Chad, Egypt, Eritrea, Ethiopia, Libya and South Sudan.

So far, more than 30,000 people have arrived in Chad, which was already hosting 400,000 refugees from Sudan, many of whom fled fighting in the western region of Darfur. More than 20,000 people have also arrived in South Sudan, said Raouf Mazou, the assistant high commissioner for operations at the U.N. refugee agency. Egypt had also taken in about 14,000 people since the fighting began on April 15, Mr. Mazou said.

The fighting has been most intense in major cities like Khartoum and Omdurman but has also spread to Darfur. Many Sudanese worry that the clashes will intensify in major cities as foreign governments finalize evacuation plans for their citizens and diplomatic staff.

Sudan was hosting 1.3 million refugees from several neighboring countries, as well as Syria, before the latest violence broke out. Many were gravitating to major towns and cities seeking work and help from aid agencies. But a prolonged fight means aid agencies will be forced to halt or limit those operations.

Several aid agencies have already suspended operations in the country or have left their local staff members running slimmed-down outfits. On Monday, the World Food Program said it would resume its services in Sudan, weeks after it halted operations following the killing of three staff members.

The United Nations has predicted that a majority of the refugees fleeing the violence in Sudan would be Sudanese nationals, but more than 200,000 South Sudanese refugees are also expected to return home to even more difficult circumstances, the agency said.

Humanitarian organizations have begun preparing contingency plans to receive refugees in neighboring countries. But aid officials say the locations face significant challenges, including volatile security and difficult supply chains.

As the number of refugees grows, aid agencies will also need increased funding, personnel and relief supplies, said Allison Huggins, the deputy regional director for Africa at Mercy Corps, a nongovernmental organization.

“This conflict would not only have catastrophic consequences for Sudan, but also for neighboring countries,” Ms. Huggins said. “Any prolonged period of insecurity would have far-reaching consequences for the region, impacting the economy and the growing refugee population.”