Military aircraft from Sudan crossed the new international border with South Sudan and dropped bombs Thursday in and around a camp filled with refugees fleeing violence in the north, officials said. At least 12 people were killed. The violence in and near the Yida refugee camp, located 10 miles (15 kilometers) south of the border, came one day after bombings were reported in another region of South Sudan, an attack that provoked strong condemnation from the U.S. State Department. The president of South Sudan, which became the world's newest country only four months ago, said he fears the Khartoum-based government intends to invade the south soon. "Whatever allegations Khartoum labels against the Republic of South Sudan are baseless, but intended to justify his pending invasion of the south," President Salva Kiir said. He later added: "We are committed to peaceful resolutions to any conflict but we will never allow our sovereignty to be violated by anybody."