News agencies say four Cameroonian soldiers have been arrested for their involvement in a disturbing video which has caused outrage on social media.

In the clip men wearing military fatigues shoot two women, including one with a baby on her back, and a little girl.

They are heard accusing the victims of being connected to the Islamist militant group, Boko Haram.

Both the UK and the US have expressed concern over the video and have called for those involved to be held accountable for their actions.

Details of the arrests are still unclear, but a spokesperson for the government denies they took place. Communications Minister Issa Tchiroma Bakary told the BBC that the government did not yet know the origins of the video.

He added that there were two versions of the clip: one where soldiers were wearing Cameroonian uniforms, and another where they appeared to be wearing Malian ones.

Amnesty International said it had credible evidence that the men in the video were indeed Cameroonian soldiers based on an analysis of their weapons, speech and uniforms.

Two military sources told the Reuters news agency the video was filmed in 2014 or 2015, in the early months of Cameroon's operations against Boko Haram.

The Cameroonian army is deployed in the country's Far North region to counter frequent incursions by Boko Haram fighters from Nigeria, where they are based.

Rights groups have accused the Cameroonian armed forces of carrying out war crimes in their fight against the militant group.