A governor in a border state has set a one-week deadline for 12,000 ethnic South Sudanese gathered south of Khartoum to leave the country, state news agency SUNA reported on Sunday. \"The wali (governor) of White Nile state, Yusuf al-Shambali, confirmed that he has set May 5 as the deadline for the Southerners waiting in Kosti,\" a way station south of Khartoum, it said. \"The presence of Southerners in Kosti threatens the security and the environment for Kosti citizens,\" he said.