ISIS has published a video through social media showing the beheading of a Russian intelligence officer who was captured in Syria, according to the US-based SITE monitoring website.

Russian authorities have not yet commented on the issue.

The footage, which was released on the day Russia celebrates the anniversary of the 1945 victory over Nazi Germany with military parades, depicted the Russian intelligence officer dressed in a black jump suit in the desert, urging other Russian agents to surrender.

During the 12-minute Russian-language video, the man said, “This idiot believed the promises of his state not to abandon him if he was captured.”

He was then beheaded with a knife by a bearded man.

The authenticity of the footage and identity of the victim could not be verified. And it is not still clear when the killing occurred.

According to Al-Masdar News, the Russian spy was said to be gathering information on the terrorist group and secretly leaking it back to the Kremlin.

His main task inside ISIS task was to befriend the late Omar Al-Shishani.

He had also infiltrated other terrorists groups in Syria, Turkey and the Caucasus on behalf of Moscow.