In Sudan, at least 435 children have been killed and at least 2,025 injured since violence broke out three months ago, according to a statement issued by the UN children's agency UNICEF on Monday.
"The impact that this conflict has had on children in Sudan over the last 100 days is unfathomable," said Ted Chaiban, UNICEF deputy executive director.
In total, the UN children's agency has received reports of 2,500 child rights violations so far, but the number is likely to be much higher, the statement said.
"Every day, children are killed, injured, abducted and witness schools, hospitals and vital infrastructure being damaged, destroyed or looted," said Chaiban, who is currently in Sudan.
More than 3.3 million people have been displaced by the ongoing violence in Sudan, according to the UN refugee agency (UNHCR).
Of these, some 740,000 people have fled to neighbouring countries, the organization reported in Geneva on Monday.
The head of the UNHCR Filippo Grandi said: "This has to stop. It is time for all parties to this conflict to immediately end this tragic war."
Until dialogue is established between both warring parties, he said, refugees must be protected from violence.
Conditions in the host countries of Egypt, Ethiopia, South Sudan, Chad and the Central African Republic are "atrocious," the UNHCR complained in its statement. Refugee centres are overcrowded, it said.
Furthermore, the many internally displaced people within Sudan are facing similar capacity problems. The current rainy season is hampering the work of aid organizations and the transport of refugees, the UNHCR reported.
Those affected are suffering from sharply rising prices for food and fuel, it said.
Sudan has been roiled since mid-April by an armed conflict between the army and the rival paramilitary militia, the Rapid Support Forces (RSF).
Former Sudanese vice president Mohammed Hamdan Daglo's RSF - made up of tens of thousands of fighters that emerged from Arab militias in Darfur - is fighting the armed forces led by the de facto president, Abdel Fattah al-Burhan.
A series of truces, brokered by Saudi Arabia and the United States, has since largely failed to hold amid a growing humanitarian crisis.
