'Grave concern' over Sudan, Rice says UNITED NATIONS, Jan. 31 (UPI) -- Washington supports a sustained peacekeeping mission in South Sudan through 2013 in response to rising violence, the U.S. envoy to the United Nations said. South Sudan and Sudan moved closer to war after disputes erupted over oil. South Sudan cut oil production in response to alleged stealing by the government in Khartoum. U.S. Ambassador to the United Nations Susan Rice said she supported calls from U.N. officials for a force of 7,000 peacekeepers for the U.N. mission in South Sudan through 2013. Rice said recommendations from Edmond Mulet, assistant secretary-general for peacekeeping operations, were something the U.S. government "strongly supports" based on the deteriorating security situation in the region. "We expressed also our grave concern, which you have heard us repeat, about the deteriorating situation in (border states) South Kordofan and Blue Nile," Rice said. South Sudan became an independent nation in July as part of a peace agreement reached with Washington's help in 2005. Lingering disputes over border and oil are complicated by ongoing ethnic conflicts in the border regions separating the countries. The independent Sudan Tribune reported Monday that Sudanese military officials urged the country's leaders to avoid war with South Sudan citing widespread corruption and the inability to control border conflicts.