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Newly arrived refugees at a camp along the volatile South Sudan-Sudan border say renewed fighting between rebels and Sudan's military is likely to send thousands more people to an expanding camp here filled with refugees of war and hunger.

Two teenagers -- Abdul Karim Mustafa and his neighbor Zeinab Abdallah Kuwa -- are looking forward to beginning school in October at the Yida camp. The two say classes will help them forget the violence they left behind.

The two traveled to Yida from the town of Tuna, in South Kordofan state in Sudan. South Kordofan has been gripped by the violent struggle between the rebel SPLA-North -- a force once allied with what is now South Sudan's military -- and the Sudanese Armed Forces. The fighting began in June 2011 following disputed gubernatorial elections.

As the fighting intensified, tens of thousands began streaming into South Sudan. Since February, the population of Yida has skyrocketed from 17,000 to around 65,000 refugees.

Mustafa, 15, and Kuwa, 18, left home on Sept. 11 and walked four days in order to reach Yida. The two drank water from rivers and accepted food from well-wishers. They brought nothing but the clothes they wore.

In its efforts to quell the rebels in South Kordofan, Sudan has routinely employed crude bombs rolled from the backs of Antonov warplanes to target the SPLA-North fighters. But the bombs often fall in civilian areas. After months of bombings, many were unable to plant their crops and took refuge in nearby caves in the Nuba mountains. Others simply fled south. Those fleeing often cross the paths of Antonov airplanes continuing their campaign against the rebels.

On the second day of their trip, the two teenagers said they encountered the war planes near the town of El-Buram, just south of South Kordofan's capital, Kadugli. Sitting in Yida just one week later, Mustafa said the planes caught him and Kuwa by surprise. His eyes -- the right is colored by a cloudy white cataract -- darted to the ground as he described what happened.

"We didn't even have time to turn around," Kuwa said. "As soon as we heard the plane, we dropped down and the bombs hit."

When the two stood up, they found that six people from the group they were walking with had been injured. One had been killed. The bombing took place a 30-minute walk away from El-Buram. There were a few scattered houses along the way but they were mostly empty. "Those people were already in Yida," Mustafa said.

Ryan Boyette, a former American aid worker who now lives in the Nuba Mountains of South Kordofan, said Wednesday that Sudanese war planes have dropped 81 bombs on 11 villages since early August. He believes Sudan is increasing its attacks to discourage the implementation of a humanitarian agreement signed Aug. 4 that would see aid deliveries to the region.

Boyette -- who runs a media website called NubaReports.com -- said hospitals in Nuba are seeing the highest numbers of malnourished children since the fighting began in 2011. Sudan's government does not allow aid groups to operate in the region.

At Yida's registration center, new arrivals relay stories of fresh fighting in the war-torn state. Yusif Ibrahim Adam, a refugee, said fighting erupted around Abu Hashim, in between Kadugli and Umm Dorain, just over a week ago.

"The Sudanese Armed Forces are now in control of Abu Hashim," he said.

Yusif al Farik came to Yida with his daughter Sara from Dolakha, just south of Kadugli. Al Farik said Sudanese forces occupied the town around Sept. 10th, killing two dozen rebel soldiers. After two days, Farik says the rebels regrouped and retook the town. "The civilians were scattered," he said.

Several new arrivals, including al Farik, say the new round of fighting has included shelling into civilian areas under SPLA-North control.

Al Noor Tutu Kafi, a 64-year-old who goes by the title chief, said he hears the same thing from new arrivals from his region. Kafi tries to gather information about how many more refugees might be on their way.

"We are expecting all the people to come. No one will remain behind because the war is going on and the bombings are still going," he explained.

When the war started, many residents -- especially children -- remained behind to continue with school and help elderly and sickly residents who could not make the journey. There were no schools in Yida, and some children who came earlier even returned to South Kordofan to continue their education. Now community leaders like Kafi say most of the schools in the war-torn region have closed, while dozens have opened in Yida.

Kafi also represents Mustafa and Kuwa. It was in front of Kafi's new, makeshift home in Yida where the pair explained that they also came for school. A wizened man with a beard and a clean white cap atop his head, Kafi says he is grateful that the two survived the journey.

After the bombing in El-Buram, the teens rested briefly before continuing south. Again the two encountered Antonovs just outside of El-Buram, but the planes did not drop bombs.

The rainy season has made the roads into the camp nearly impassable, but people are still arriving. With ongoing fighting and the resulting hunger, the U.N. refugee agency believes there could be an additional 15,000 refugees in the camp by the end of the year. If the war continues, community leaders say such an influx is likely.

Mustafa said Sudanese forces began shelling his hometown, Tuna, on Aug. 19, during the the Muslim celebration of Eid al-Fitr. Abdul said a shell hit one house in his village, but nobody was inside.

"They were already here in Yida," he said.