Government says another footage with Tamil voice has now emerged

Journalists for Democracy in Sri Lanka (JDS) say that the "newly emerged" video was first published in a pro government website on 18 September 2009.

JDS also calls upon the government to submit the clip to an international investigation for authentication.

The Sri Lankan government claims that the video contains Tamil Tigers committing a crime against Sri Lankan soldiers.

Sanath Balasuriya, a spokesman for JDS told BBC Sinhala service that the new claim invalidates the government's previous claim that such an incident never occurred.

'An admission'

"In a report by a so-called group of experts, the government said it was staged and not something that actually happened. If the government now says that the video shows a crime committed by the LTTE, it is an admission that such an incident did actually happen," he said.

In a report by a so-called group of experts, the government said it was staged and not something that actually happened. If the government now says that the video shows a crime committed by the LTTE, it is an admission that such an incident did actually happen Sanath Balasuriya, JDS

JDS provided British Channel 4 television with a video with the same visuals and Sinhala speech which apparently shows extra-judicial killings by Sri Lankan troops.

An extended version of that video has been viewed by the the UN Special Rapporteur on extra judicial, summary or arbitrary executions who concluded the incident as authentic.

Christof Heyns, described the killings shown on the video as "textbook examples of extra judicial executions."

JDS spokesman Balasuriya challenged the Sri Lankan government to provide the longer version with Tamil speech 'if it shows a crime committed by Tamil Tigers'.

Analysing video

Meanwhile, the Sri Lankan government says it is analysing video which proves the falsity of a recent television documentary that accused the country's government and armed forces of committing atrocities.

It says the evidence is contained in what it calls the original version of a piece of footage which was later used by the independent British station, Channel 4, to incriminate the army.

The BBC's Charles Haviland in Colombo says it's part of a broad government campaign to discredit the Channel 4 documentary which appeared in mid-June.

The basis of the government's counter-propaganda against Channel 4 is a segment of footage which appears to show soldiers executing prisoners.

At the same time, the government has been further dissecting the Channel 4 documentary and accusing it of bias.

The top story on the defence ministry website accuses the channel of ignoring the fact that the Tigers had killed thousands of innocent civilians.

It denounces two of the senior Tigers whose bodies were shown in another part of the documentary; and accuses one of the main interviewees of undergoing military training with the militant group.