Sudan’s minister of defense, Lt Gen Jamaleldin Omar, has died of a heart attack in South Sudan, where he was taking part in peace negotiations between the government and armed movements in Juba, a spokesman for the Sudanese army said early on Wednesday.

Omar was a member of the military Council that took power after toppling Omar al-Bashir last year and replaced with the sovereign council which runs the country under a 39-month power-sharing deal with a civilian government.

In a statement on Wednesday, the Sudanese army said Omar’s death was caused by a heart attack.

For his part, General Abdel Fattah al-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.

Held in Juba, the talks aim to stabilise the country and help its fragile path to democracy survive following the military’s overthrow of al-Bashir in April last year in the face of months-long mass protests against his rule.

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.