The last place Lina Mijok wanted to go as she fled fighting in Sudan was back to her own country, South Sudan, which she had left as civil war erupted in 2013.

But when Sudan’s army started battling the paramilitary Rapid Support Forces (RSF) in the streets around her home last month, South Sudan was the only place she and her two children could get to.

“I would not have come back to South Sudan. I would have gone anywhere, but I had no choice,” the 26-year-old said.

She had managed to carve out a new life for herself as a housemaid in Omdurman, the city across the Nile River from the capital, Khartoum.

Then shots started ringing out and her family had to pack up and leave that behind them – all of them apart from Mijok’s husband.

He had to stay behind because they did not have enough money to pay for his place on the trucks and buses that carried Mijok, their son and daughter to the border, a nerve-racking two days on bush roads.

They are now among thousands camping out in South Sudan’s Renk County on a dilapidated university campus, its buildings pockmarked by bullets from fighting a decade ago.

The refugees have made basic shelters out of sticks and pieces of fabric. The United Nations refugee agency and other aid groups are distributing food, water, blankets and mats.

The fighting has turned the humanitarian situation on its head.

Until last month, more than 800,000 South Sudanese refugees lived in Sudan. Since the fighting erupted in Khartoum, the UN High Commissioner for Refugees (UNHCR) has registered more than 30,000 people crossing into South Sudan, more than 90 percent of whom are South Sudanese, but the agency noted that the true number is likely much higher.

Aid agencies fear the influx will worsen an already dire humanitarian crisis in South Sudan, where more than 2 million people are displaced and three-quarters of its 11 million people need aid.