Rebels in a “revolutionary front” aimed at toppling the Khartoum regime on Sunday claimed their first joint attack against government forces, but the army blamed troops from South Sudan. Rebels of the Justice and Equality Movement (JEM), from the western region of Darfur, combined with insurgents from the Sudan People’s Liberation Movement-North (SPLM-N), which for several months has been fighting in South Kordofan and Blue Nile states along the border with South Sudan, JEM spokesman Gibril Adam Bilal said. Last November, the two rebel groups joined with factions of Darfur’s Sudan Liberation Army to form the front dedicated to “popular uprising and armed rebellion” against the National Congress Party government in Khartoum. “This attack is under the umbrella of the Sudanese Revolutionary Front,” Adam told AFP. He said Sunday’s offensive happened at Jau, a disputed area in an oil-rich region on the poorly defined border.