Just as countries on the U.N. Human Rights Council prepare to vote on a United States-sponsored resolution against Sri Lanka, a new video clip released by British public-service television broadcaster Channel 4 has accused the Sri Lankan armed forces of having an “underlying culture of systematic brutality and sexual violence.”

Channel 4 journalist Callum Macrae’s report of the video — with a clip that is a little over six minutes long — was released late Sunday, a week after the United Nations Human Rights Council Session began in Geneva. On March 28, member countries will vote on the U.S.-sponsored resolution, possibly calling for an investigation — aided by the Office of the High Commissioner for Human Rights — into alleged war crimes during the final phase of the Sri Lankan civil war.

Mr. Macrae’s earlier documentaries Sri Lanka’s Killing Fields and No Fire Zone: In the Killing Fields of Sri Lanka had sparked controversy around alleged war crimes and rights abuse in Sri Lanka.

On the new visual that has emerged, he said, it was unclear when the video was filmed but suggests it was at some point in the last two or three years of the war, possibly by a soldier using a mobile phone. The disturbing visuals show Sinhala-speaking, uniformed men apparently celebrating over bodies that the report identifies as those of female Tiger fighters. “Taken with all the other evidence which has emerged — and continues to emerge — this suggests a pattern which, in an army as disciplined and effective as the Sri Lankan one, means that command responsibility for these actions could be traced to the very top of the armed forces and government,” Mr. Macrae has said in a statement.

The video footage came from the British Tamil Forum — an umbrella organisation for several Sri Lankan Tamil diaspora groups based in the United Kingdom.

When contacted, Army spokesperson Ruwan Wanigasooriya denied the allegations and said that the latest video was “only an extension of Channel 4’s already well-known campaign to discredit the Sri Lankan government and armed forces.”

Brigadier Wanigasooriya also said that Channel 4 was aligned with Tamil diaspora sections that are sympathetic to the rebel Tigers, and are still espousing the separatist cause. Speaking to The Hindu over telephone from London, Mr. Macrae said he had been extraordinarily careful in having the video content authenticated.

Asked if the source of the content made him additionally sceptical, he said: “No matter where we get it from, we are very, very careful. I couldn’t be more sceptical than I am, and we have been very careful in getting the images authenticated by independent video analysts and leading forensic pathologists.”

Responding to the Sri Lankan army’s charge that Channel 4 was strategically releasing its footage to reach out to countries voting this year, Mr. Macrae said it was a “genuine, complete coincidence.”

“We got the footage recently and it took time for us to verify its authenticity. All the same, I am not ashamed at releasing it now, ahead of the UNHRC session. As a journalist, it is my job to put it out ahead of an important event,” he said.