Elements of Sudan’s military have acted to protect protesters in Khartoum after security forces fired tear gas to break up a mass sit-in, eyewitnesses say.
Soldiers tried to chase away pick-up trucks firing tear gas, on the second night of a sit-in protest calling for President Omar al-Bashir to resign.
Protesters sought shelter in a navy facility, a witness said, as divisions among the armed forces were laid bare.
Mr Bashir has so far refused demands to make way for a transitional government.
One protester told the BBC’s Newsday that a number of pick-up trucks arrived and began firing tear gas and live ammunition at the thousands of sit-in protesters in the Sudanese capital.
She said the military was at first neutral but then tried to chase the security forces away.
It is unclear who the security forces were but BBC Africa editor Fergal Keane says reports indicate they were from the national intelligence service and a state militia.
The eyewitness said the security forces returned for a second attack and people then ran towards a navy facility to seek shelter from the prolonged firing.
Ali Ibrahim, of the Sudanese Professionals Association (SPA), which has organised the protest, told EFE news agency that military units had fired into the air to prevent security forces dispersing the sit-in.
There are unconfirmed reports of casualties from the scene. Video on social media showed protesters hiding behind walls as shots ran out
One resident of a district 5km (3 miles) away told Reuters the tear gas could be felt there.
The sit-in is taking place outside the army HQ and Agence France-Presse quotes witnesses as saying the army has now deployed troops around the building and is erecting barricades in streets near the compound. The army’s intentions surrounding the protest remain unclear.