CAIRO (AP) — Sudan’s defense minister, Gen. Gamal al-Din Omar, died Wednesday of a heart attack while on an official visit to neighboring South Sudan, Sudanese military and government officials said Wednesday.

Omar was in South Sudan’s capital of Juba, taking part in peace talks between his country’s transitional government and rebel groups, the officials said. He attended meetings that stretched into late Tuesday and died early Wednesday, the officials said. The was no further information.

The officials spoke on condition of anonymity because they were not authorized to talk to the media.

Omar was a member of Sudan's Sovereign Council, which took power last year under a 39-month power-sharing deal between the country's military and the pro-democracy movement that led the uprising against former autocratic President Omar al-Bashir.

In a statement released later Wednesday, Gen. Abdel-Fattah Burhan, who heads the Sovereign Council, said he mourned the death of Omar “who died while struggling for the stability of Sudan” — a reference to talks with rebels to end Sudan’s years-long civil wars.

Sudan’s transitional government has been engaging in peace talks with rebel groups since October. Juba, the South Sudanese capital, is hosting those negotiations which aim to stabilize the country and help its fragile path to democracy survive following the military’s overthrow last April of al-Bashir, who held on to power for nearly three decades.

Hundreds of thousands of people have been killed in fighting in Sudan’s multiple insurgencies, including in the restive western Darfur region. That’s where al-Bashir brutally repressed an uprising in the early 2000s. Since then, the International Criminal Court has sought al-Bashir on charges of war crimes and genocide.

Reaching a peace deal with the rebels is crucial to Sudan’s transitional government as it seeks to rehabilitate the country’s battered economy, attract much-needed foreign aid and deliver the democracy it promises.