The Yida refugee camp in the recently formed nation of South Sudan - home to 20,000 people - was hit by a bomb on Thursday, witnesses said.
Many feel the government of Omar al-Bashir, the president of Sudan, is to blame.
South Sudan split from Sudan in July following decades of war between north and south. But some border areas remain poorly defined and are being fought over.
Al Jazeera's Caroline Malone reports.