More than 400 people have been killed in Sudan amid days of violence between the army and a powerful paramilitary force, raising fears of a wider conflict that could destabilize the region. At least 3,500 have been injured in the last six days alone, the World Health Organization said. True casualty numbers are expected to be much higher. According to the United Nations, the fighting has been “almost uninterrupted.” Airstrikes, gunfire and artillery have rocked the capital, Khartoum, but the violence is spreading to other areas, too.