The paramilitary Rapid Support Forces (RSF) has killed 27 people in a reported drone attack on a Sudanese army base in the southeastern city of Sinja, a military source told Al Jazeera. Monday's attack coincided with an announcement a day prior that the government, aligned with the Sudanese Armed Forces (SAF), would be returning to the capital, Khartoum, three years after it had shifted its base of operations to Port Sudan. The military source, who spoke to Al Jazeera on condition of anonymity, said Monday's drone attack targeted not only leaders in the government forces but also the security teams and civilians accompanying them. It was unclear how many people were wounded in the attack. Al Jazeera received reports that 13 people were injured, while some estimates have put the number much higher.

Sudan's army leader, General Abdel Fattah al-Burhan, says the military will not join talks next month in Switzerland aimed at ending more than a year of fighting with the paramilitary Rapid Support Forces (RSF). Al-Burhan made the statement on Wednesday, shortly after the military said he survived a drone strike on a military graduation at the Gibeit army base in eastern Sudan that killed at least five people. "We will not retreat, we will not surrender and we will not negotiate," al-Burhan told troops. "We are not scared of drones," he said at the Gibeit base, which is about 100km (62 miles) southwest of Port Sudan, where the army-aligned government fled after war broke out with the RSF in April last year. The fighting has created the world's largest displacement crisis and killed at least 15,500 people, according to United Nations estimates. Video of the drone attack, verified by the Reuters news agency, showed soldiers marching in a graduation ceremony before a whirring sound can be heard.