The reported defection comes as Sudan’s army attempts to push back its former ally, the paramilitary RSF.

Sudan’s army said on Sunday a commander from its foe the Rapid Support Forces (RSF) had defected with some of his troops, in what would be the first such move by a senior figure since the sides started fighting more than 18 months ago.

There was no immediate comment from the RSF, which has seized control of large parts of the country in a conflict with the military that the United Nations says has caused one of the world’s worst humanitarian crises.

Supporters of the army posted photos online purporting to show Abuagla Keikal – a former army officer who became the RSF’s top commander in the southeastern state of El Gezira – after he had defected.

The army, which has recently made gains against the RSF in parts of the capital Khartoum, said Keikal had decided to make the move because of his former force’s “destructive agenda”.

It did not go into further detail and there was no statement, in print or on video, from Keikal.

The army has also claimed an advance in the state of Sennar, in southeast Sudan near the border with Ethiopia, opening up a supply route from eastern Sudan into the south.

Reporting from Khartoum, Al Jazeera’s Hiba Morgan said Keikal was the most senior RSF commander in El Gezira state.

“[The army] said that any other fighter from the RSF who wants to come and join ranks with the army is welcome to do so,” said Morgan.

The conflict has displaced more than 10 million people, driven parts of the country to extreme hunger or famine, and drawn in foreign powers that have supplied both sides with material support.

It began in April 2023 when tensions between the RSF and the army, who had been jostling for position before an internationally backed transition to civilian rule, erupted into open conflict.

The army and the RSF had previously shared power after staging a coup in 2021, two years after veteran leader Omar al-Bashir was toppled in a popular uprising.