DAKAR - Hundreds were killed in north-central Burkina Faso on Saturday after suspected jihadists opened fire on them as they were digging trenches around a town to protect it from attacks, victims' relatives and a source who spoke to wounded survivors said.

The attack outside the town of Barsalogho is one of the deadliest since groups linked to al Qaeda and Islamic State moved into Burkina Faso from neighbouring Mali almost a decade ago, plunging the Sahel nation into a security crisis that contributed to two coups in 2022.

The ruling junta has condemned the violence, but did not say how many people were killed.

Hundreds of wounded people were evacuated to healthcare facilities in the city of Kaya, around 40 kilometres (25 miles)south, where a source who did not wish to be named for fear of retribution said the death toll from the attack was likely higher than 500.

Speaking via telephone on Tuesday, the source said Burkina Faso troops had forced reluctant Barsalogho residents to stop their daily activities and dig trenches around the town to deter insurgents.

Hundreds were at work outside when suspected jihadists attacked, the source said, citing the accounts of several injured victims in Kaya.

"All they could do was lie down on top of each other. It was carnage," the source said, adding that gunmen also shot at women who were collecting firewood nearby.

Relatives of Barsalogho residents in the capital Ouagadougou issued a joint statement on Sunday relaying a similar chain of events.

They said at least 400 people had been killed, either on the spot or succumbing to injuries later, and that hundreds more were hospitalised between Kaya and the capital Ouagadougou.

Reuters has not been able to independently verify the estimated death toll.

The statement accused the army of forcing residents to dig the trenches, beating those who feared reprisals for visibly siding with authorities in an area rife with violent insurgent activity.

Junta spokesman Jean Emmanuel Ouedraogo did not immediately respond to a request for comment. He headed a delegation of officials that visited hospitalised survivors in Kaya on Sunday and Barsalogho on Monday.

"The government joins you in prayers for the souls of the deceased," Ouedraogo told local media during the trip, saying that jihadists had killed people engaged in "community work."

He lauded health workers, and said the government would cover medical bills and provide humanitarian support.

Civil society have organised blood donations in Kaya, where the diocese declared a day of mourning on Wednesday.

The United States embassy in Ouagadougou on Tuesday said the U.S. "strongly condemns the terrorist attack".

No group has directly claimed responsibility for the bloodshed. Al Qaeda affiliate Jama'a Nusrat ul-Islam wa al-Muslimin said it had seized control of suspected army headquarters in Barsalogho on Aug. 24.

  - Reuters