The 13-year conflict in Sudan’s vast Darfur region is now limited to the Jebel Marra area as a result of the government’s successful counter-insurgency strategy against two rebel groups, U.N. experts said in a report circulated Monday.

The experts said Sudanese military action has forced the Justice and Equality Movement or JEM to leave Darfur and operate mostly in neighbouring South Sudan and the Sudanese Liberation Army faction led by Minni Minawi to operate mainly across the border in Libya.

In Jebel Marra, forces loyal to the Sudan Liberation Army’s founder Abdul Wahid Elnur continue to hold pockets of territory and fight government forces, the experts said in the report to the U.N. Security Council.

Darfur, which is the size of Spain, has been in turmoil since 2003, when ethnic Africans rebelled, accusing the Arab-dominated Sudanese government of discrimination. Khartoum is accused of retaliating by arming local nomadic Arab tribes known as the janjaweed and unleashing them on civilian populations — a charge the government denies.

In addition to Jebel Marra, the experts said “localized intercommunal violence, militia activity and banditry have continued unabated in the five states of Darfur.”

The United Nations says at least 300,000 people have died in the conflict and the panel said humanitarian experts estimate over 2.6 million have fled their homes.

The experts said the government has pursued a peace agreement on its own terms with JEM, which it said has been based in South Sudan since 2012-2013 with support from its government, and Minawi’s SLA fighters, which it said has been in Libya since mid-2015 according to reliable sources. So far, government peace efforts have failed.

“Away from the military pressure of the government of Sudan,” the experts said, “they aim to rebuild their capability using the revenues obtained from their current mercenary and criminal activities.”

In Jebel Marra, the experts said Elnur’s SLA fighters continue to fight even though they are weakened and are unlikely to join the peace process in the near future. They added that his rebels’ losses “have fueled tensions” about his leadership and strategy and sparked some defections.

The government has blocked the joint U.N.-African Union peacekeeping force known as UNAMID from Jebel Marra, and the experts said they have not received promised visas to visit Darfur.

When they do, they said they plan to investigate allegations that government forces carried out aerial bombings in Jebel Marra with air-to-ground weapons in possible violation of a U.N. ban on offensive military overflights and an arms embargo.

The experts also plan to investigate possible violations of human rights and international humanitarian law, and allegations by Amnesty International in September that Sudan used chemical weapons in its offensive in Jebel Marra — which the government has denied.

The experts’ report follows the Obama administration’s announcement last Friday that it was ending the U.S. economic embargo on Sudan and lifting trade and financial sanctions in an effort to expand ties with the long-estranged government and build on positive signs of co-operation against Islamic extremism.