Col. Gen. Sergei Rudskoi of the Russian General Staff speaks to the media in the Defense Ministry in Moscow, Friday, May 5, 2017, about an agreement to set up four de-escalation zones in Syria. (Pavel Golovkin/AP)

The Islamic State released a video showing the beheading of a Russian intelligence officer it accused of spying on the group in Syria.

The video, which was released on media accounts associated with the Islamic State on Monday, showed the gruesome murder of Capt. Yevgeny Petrenko, 36, who the Islamic State said had infiltrated Islamist groups in Kazakhstan and the North Caucasus region of Russia before he was caught last year by the Islamic State in Syria.

The video was accessed through a copy provided on the site of the SITE Intelligence Group, which monitors extremist publications and media. It confirmed the video on Tuesday.

In an interview apparently given under duress, Petrenko, an agent for the Russian Federal Security Service (FSB), said he had been abandoned by the Russian government and called on it to end its military campaign in Syria.

“I was supposed to infiltrate the special services of the caliphate and the leadership of the caliphate,” the man identifying himself as Petrenko, dressed in a black button-down shirt and a black hat, told an interviewer whose face was obscured. “One of my orders was to gain access to Omar al-Shishani or to his circle. But during this, I was discovered and arrested by the security services of the caliphate.”

Shishani is a Georgian Chechen commander for the Islamic State in Syria who is said to have been killed in 2016. The Pentagon once called him the Islamic State’s “minister of war.”

Thousands of Russian-speaking fighters have flocked to join the Islamic State, largely from the North Caucasus region of Russia and former Soviet republics in Central Asia. Russia has made it a priority to prevent them from returning to the country and carrying out terrorist attacks.

Russia launched a military campaign in Syria in September 2015 to back the government of President Bashar al-Assad against a wide array of rebel and Islamist groups. Increasingly, that has made Russia a target for terrorism, including the 2015 bombing of an airliner by an Islamic State-affiliated terrorist group in Egypt.

Nevertheless, videos showing the killing of Russian soldiers or spies are rare. The latest video named two men, Sergey Ashimov and Jambulat Mamayev, whom the group arrested in 2015 and accused of working as FSB agents. The two men were shot execution-style by a child in a 2015 propaganda video put out by the Islamic State. The video also named several others who had allegedly been delivering information to the Russian FSB.

News of Petrenko’s detention first surfaced in a video last year called “Message From a Russian Intelligence Officer Captured by the Islamic State: To the President of Russia and Its People.”

Islamic State media channels have published a steady stream of execution videos as the group’s territory has been rolled back, apparently attempting to project power through what amount of carefully choreographed horror films instead of through military gains. The films most commonly feature the murder of Syrian soldiers, militiamen or activists opposed to the extremist group’s brutal rule.

Under pressure from an array of forces throughout its self-proclaimed caliphate, the Islamic State has lost two-thirds of the territory it captured across Syria and Iraq in 2014. The defeats are believed to have strained the group’s finances, which were heavily dependent on the ability to tax and extort populations under its control.

In Iraq, a U.S.-led coalition is now backing Iraqi ground troops in a grueling seven-month-long fight to recapture the Islamic State bastion of Mosul. In Syria, Kurdish militants, backed by the United States, are edging closer to Raqqa, the Islamic State’s main stronghold and de facto capital, setting the stage for a bloody showdown in the city.

Louisa Loveluck in Beirut contributed to this report.