Hostilities haven't ceased despite the agreement that ended the decades-long civil war. As aid blockades and bombings of civilians continue, the international community mostly stays silent.

When South Sudan declared independence in July, the international community breathed a sigh of relief. A difficult six-year process, set forth in the ambitious 2005 peace agreement that ended Sudan's 22-year-long civil war, was finally over. The world appeared to feel it could stop focusing on Sudan.

But Sudan's wars have not ended. They have, in fact, multiplied. Five of Sudan's 16 states are mired in armed conflicts. Since June, new conflicts have erupted in two volatile states — Southern Kordofan and Blue Nile — just north of the South Sudan border, while the three states in the western region of Darfur are still a war zone, although that conflict has dropped from the headlines. These conflicts are a stark reminder that the 2005 agreement failed to address the root causes of Sudan's problems. They are also a reminder that without justice, there can be no lasting peace in Sudan.

In a grim reprise of the civil war, the Sudanese government of President Omar Hassan Ahmed Bashir has been fighting armed opposition groups with historical links to the former southern rebels, the Sudan People's Liberation Movement/Army (SPLM/A), in Southern Kordofan and in Blue Nile. Both states are home to ethnic African populations whose grievances and injustices were not appropriately addressed in the 2005 peace agreement or in its implementation. Adding insult to injury, the governor of Southern Kordofan is Ahmed Haroun, who, along with President Bashir, is wanted by the International Criminal Court for crimes committed in Darfur.

Fighting broke out in Southern Kordofan in early June following hotly disputed state elections, in which Haroun narrowly claimed the governorship for a second term, and in the context of government attempts to disarm the Sudan People's Liberation Army. The violence has included heavy shelling, widespread arrests, destruction of property and massive population displacement. It has been accompanied by a campaign of indiscriminate bombing, killing scores of people and wounding many more.

During our August trip to the Nuba Mountains in central Sudan, where more than 200,000 people have fled their homes, we witnessed aircraft on a near-daily basis dropping bombs and causing families to scatter. We found large numbers of people in caves and on mountaintops, terrified to return to their villages.

In early September, the fighting spread to neighboring Blue Nile, where Bashir declared a state of emergency and sacked the opposition governor. Government security forces arrested dozens of suspected sympathizers. As in Southern Kordofan, ground battles are ongoing while the government indiscriminately bombs civilian areas. More than 30,000 people have fled, most across the Ethiopian border.

In both states, the government has imposed a cruel aid blockade — in total disregard of international law and of repeated requests for access by United Nations and nongovernmental aid groups — preventing food and other goods from reaching needy civilian populations in opposition-held areas. The people in the Nuba Mountains are surviving on dwindling rations, supplemented by leaves and berries. The persistent bombing has prevented them from cultivating crops, raising fears of malnutrition and famine in coming months.

In these marginalized areas, as in Darfur, Sudan is violating basic precepts of international law with total impunity. The world has been too divided on Sudan, and too silent. Neither the U.N. nor the African Union has uttered a peep of condemnation for Sudan's actions in Southern Kordofan and Blue Nile, even though the U.N. Office of the High Commissioner for Human Rights warned that war crimes and crimes against humanity may have occurred in Southern Kordofan.

The U.N. and the African Union should demand an end to Sudan's bombings, call for unfettered access for humanitarian agencies and press for the immediate deployment of an independent human rights monitoring presence. The United States should push for these actions at the U.N. Security Council and with key African partners. And it should remind other powers that Bashir continues to commit them elsewhere in Sudan.

Sudan's conflicts all have the same root causes: the Arab-majority government's economic and political marginalization and neglect of far-flung regions and populations of African ethnicity, and the use of military force to subjugate them rather than guaranteeing democratic reforms and respect for human rights.

But the 2005 peace agreement did not force Sudan to change its ways. Although the parties carried out parts of the agreement — elections in 2010 that were deeply flawed and a referendum on southern independence last January — they did not implement the ambitious reforms that could have helped address some of the inequities driving Sudan's conflicts. It is no small wonder that the South chose to secede.

Sadly, for those of us who have followed the situation in Sudan for many years, the new wars were predictable. International supporters have repeatedly failed to press Sudan to make needed reforms or hold Sudan accountable for serious abuses — so the abuses continue. If the United States and others don't insist that Sudan make changes, the conspiracy of silence will continue to perpetuate the myth that Sudan's long war is over, when for many it is starting up again.

Jehanne Henry is a senior Africa researcher and Gerry Simpson is refugee policy advocacy director at Human Rights Watch.