An Islamist militant group in Russia’s North Caucasus asserted responsibility Sunday for twin suicide bombings in the southern city of Volgograd last month and posted a video threatening to strike the 2014 Winter Olympics in Sochi.

There had been no previous claim of responsibility for the bombings, which killed 34 people and heightened security fears ahead of next month’s Winter Games.

In the video, two Russian-speaking men warned President Vladimir Putin, “If you hold these Olympics, we will give you a present for the innocent Muslim blood being spilled all around the world — in Afghanistan, in Somalia, in Syria.”

They added, “For the tourists who come, there will be a present, too.”

In a statement posted with the video on its Web site, the militant group Vilayat Dagestan said it was behind the Volgograd bombings.

The video claims that the two men, identified as Suleiman and Abdurakhman, were the suicide bombers and purports to show the explosives being prepared and strapped to their bodies.

The Russian security services did not comment on the video.

During much of the 49-minute video, the two men speak to the camera while holding Kalashnikov automatic rifles. Behind them hang black banners emblazoned with Arabic religious phrases similar to those used by the al-Qaeda terrorist network.

Vilayat Dagestan is one of the groups that make up the Caucasus Emirate, which seeks to establish an independent Islamic state in the North Caucasus, a region just to the east of Sochi on Russia’s southern border.

Dagestan, one of several predominantly Muslim republics in the North Caucasus, has become the center of the Islamist insurgency that has spread throughout the region after separatist wars in neighboring Chechnya.

Even before the Volgograd bombings, Russia had introduced sweeping security measures for the Sochi Games.

The Chechen leader of the Caucasus Emirate, Doku Umarov, had ordered a halt to attacks on civilian targets in 2012, but he rescinded that order in July and urged his followers to try to undermine the Olympics.

The Kremlin-backed leader of Chechnya asserted last week that Umarov was dead, but the claim could not be verified.

— Associated Press