On a wide plain of cracked earth and yellow grass deep in Sudan's Nuba Mountains, rebel commander Brigadier General Namiri Murrad raises a pair of binoculars and studies his objective, the government-held town of Talodi, some 4 km away. "They have three tanks, you see?" he says, passing over the field glasses. "They had six, but we destroyed three. They also have .50-cals. and 12.5s [heavy machine guns] in the hills above. But I have 3,000 men and two more brigades of 2,000 to 3,000, and they have just 1,700 to 1,800. We'll finish this quickly." He regards the dust cloud kicked up by our cars when they approached the front line, then looks up at the sky. "They send Antonovs and MiGs to bomb us when they see trucks moving," he says. "We leave now."
Namiri is a Nuba field commander spearheading a new rebel attempt to overthrow Sudanese President Omar Hassan al-Bashir and his Islamist regime in the capital of Khartoum. "Right now, our work is to clean our house," he says. "Our allies in Darfur and Blue Nile will also clean their houses. Then we will move together on Khartoum. Some of them will die, some will run away. We will finish them." It's a simple plan, but it's important for a simple reason: the Nuba are suddenly winning.
Sudan has rarely known peace. Since independence from Britain in 1956, civil war has cost 2 million lives. The dynamic has rarely changed: an autocratic Arab, Islamist, centrist state in the north vs. poorer, more African and less Muslim rebels to the south. The Nuba rebels fought with the south, but when South Sudan split to form a new country last year, Southern Kordofan, where the Nuba Mountains are located, found itself on the northern side of the border, along with two other rebel provinces, Darfur and Blue Nile.
Last June, smarting from South Sudan's approaching independence and fearing further loss of power in a Southern Kordofan election, Khartoum ordered its security forces to suppress the Nuba opposition. TIME documented how Sudanese police and soldiers went house to house in Kadugli, the state capital, executing activists and fighters. Within hours, that escalated to ethnic cleansing. Southern Kordofan Governor Ahmed Haroun, already accused by the International Criminal Court of committing war crimes in Darfur, said in a speech broadcast on state radio, "Do not leave a single person [there]. Clear them out. Bring them alive. Eat them raw." Khartoum's warplanes bombed villages and refugee columns, prompting 125,000 to flee to nearby caves or camps in South Sudan. The Satellite Sentinel Project, an initiative by actor George Clooney to monitor Sudan from space, identified eight suspected mass graves in and around Kadugli. For the living displaced and unable to farm because of the bombing famine loomed.
But a return visit to Nuba territory this April reveals a surprise: Khartoum's assault has backfired. Nuba forces have killed hundreds of government troops, won a string of victories and captured several key settlements, including the border town of Jau and the administrative center of Trogi, as well as an arsenal of government weapons and vehicles. The acting commander of Nuba forces on the front lines, Major General Izzat Kuku, tells TIME he controls 80% of the Nuba Mountains, leaving Khartoum holding little more than the two most strategic towns, Talodi and Kadugli its most diminished position in a generation.
The Nuba formed a crucial alliance, the Sudanese Revolutionary Front (SRF), with fellow rebels in Blue Nile and Darfur. That agreement led Darfur's largest rebel group, the Justice and Equality Movement (JEM), to fight with the Nuba in Jau. The united rebels hope to open a second front in the Sudanese capital itself. Since the Arab Spring in early 2011, Sudanese security forces have violently crushed intermittent youth protests against al-Bashir's autocracy in Khartoum. Izzat claims the SRF coalition now extends to that opposition, who will "organize people in an uprising" if the rebels advance sufficiently. "We are confident," he says. "We will sweep north out of the Nuba Mountains all the way to Khartoum. We all want the same thing to change the regime in Khartoum."
That would likely be a fantasy but for one other crucial development: war has erupted between north and south. When South Sudan seceded, the precise north-south border was never settled. On April 14, JEM invaded and seized Heglig a key oil installation officially in the north but claimed by South Sudan leaving the bodies of scores of northern troops by the side of the road or floating in pools of crude. And JEM wasn't alone. Despite months of denying an alliance with the rebels, South Sudanese troops fought openly with JEM at Heglig.
Both Sudan and South Sudan responded by dispatching tens of thousands of troops to the border. Clashes were reported along the frontier. In Khartoum and South Sudan's capital, Juba, politicians banged the drums of war. On April 18, al-Bashir said those in the South's ruling Sudan People's Liberation Movement were "insects" that had to be "eliminated," saying, "This story began in Heglig, but it will end in Khartoum or Juba." In Juba, South Sudan's President Salva Kiir told supporters that world leaders had implored him to back off. "[U.N. Secretary-General Ban Ki-moon said], 'I am ordering you to immediately withdraw from Heglig,'" said Kiir. "I replied, 'I'm not under your command.'" Though Kiir did withdraw on April 20 when Khartoum's troops pushed back over the border, that retreat seems unlikely to usher in peace. Addressing the U.N. Security Council on April 18, African Union mediator Thabo Mbeki said the two sides were locked in "a logic of war."