(CNN) -- The United Nations refugee agency Tuesday condemned air raids on Sudanese refugees in South Sudan that injured at least one boy and left 14 missing.
The bombings happened Monday near the border with Sudan.
"UNHCR is alarmed by this attack on vulnerable refugees already fleeing violence in Sudan's Blue Nile state," the agency said.
There were two bombings Monday in the town of Elfoj in South Sudan, which struck near a refugee site, the U.N. agency said.
Some 5,000 refugees were at the site, a staging area from where they are moved to other settlements.
The agency was in the process of transporting refugees when the first strike took place, the agency said.
"Refugees jumped out of the trucks and scattered," it said. "Agency staff also had to seek safety."
Decades of civil war between the north and south, costing as many as 2 million lives, ended with a U.S.-brokered peace treaty in 2005.
But before South Sudan gained independence in July of last year, human rights monitors expressed concerns that long-standing grievances could lead to violence consuming the region again.
According to UNHCR, there have been previous attacks on Sudanese refugees in border areas.
In November, there were several days of bombings near an entry point for refugees at the border, the agency said. It did not specify who launched the bombs.
Overall, more than 78,000 people have fled Sudan's South Kordofan and Blue Nile states since August of last year, the agency said.