The war between Sudan’s generals is having increasingly severe consequences for civilians, with a doubling over the past week of the number uprooted from their homes, the United Nations said on Tuesday.

Hundreds have already been killed in the fighting but new worries emerged as separate ethnic clashes claimed at least 16 lives in the country’s south, and a powerful group in the east, an area so far untouched by the war, demonstrated in support of the army.

More than 700,000 people are now internally displaced by battles which are now in their fourth week, Paul Dillon, spokesman for the International Organisation for Migration, said in Geneva.

“Last Tuesday, the figure stood at 340,000.” An increasing number are also crossing borders to escape the battles between the army, led by Abdel Fattah al-Burhan, and his deputy-turned rival Mohamed Hamdan Daglo who commands the heavily armed paramilitary Rapid Support Forces (RSF).

Fighting has been concentrated in the capital Khartoum but other areas, particularly the western Darfur region bordering Chad, have also seen heavy fighting.

In addition to the internally displaced, another 150,000 have fled to neighbouring countries, the UN refugee agency said on Monday.

Those left behind in the war zones face shortages of water, electricity, food and medical care in a country where, according to the UN, about one-third of the population needed humanitarian assistance even before fighting began.

Foreign-led evacuations by land, sea and air have seen the departure of thousands of other people, many of them from the Red Sea city of Port Sudan, which has so far been peaceful.

But a demonstration on Monday in support of the army, which some called on to arm civilians, raised alarms in a country already marked by a history of ethnic unrest.

“We, all of us the Beja, are ready to be armed and to protect the land and our honour,” said Mahmoud al-Bishary, a Beja member, in a speech during the rally.

Such sentiment could signal even more problems for Sudan, where analysts see a protracted fight between the generals.