An image made from a militant video posted Sept. 11 shows abducted Turkish men seated as five armed militants in black masks stand behind them in front of a wall emblazoned in Arabic with the group’s name, Death Squads. (AP)

Purported Shiite militants threatened Turkey in a video released Friday by a previously unknown group that showed footage of 18 Turkish workers recently abducted in the Iraqi capital.

The video, which shows black-clad gunmen in front of a wall bearing a Shiite religious slogan, was a reminder of the power such groups wield against a weak Iraqi government that has been crippled by its fight against the Islamic State.

The group, calling itself “Death Squads,” demanded that Turkey prevent Sunni jihadists from entering Iraq, halt the flow of oil from Iraq’s northern Kurdish region through Turkish territory, and order its Sunni rebel proxies to lift their siege of two mostly Shiite towns in Syria.

Iraqi security officials were not available for comment Friday.

In the video, the hostages, kneeling on the ground in front of the militants, say that Turkish authorities should grant the gunmen their demands so the workers will be set free. The hostages — construction workers and engineers from a sports stadium on the outskirts of Baghdad — were kidnapped Sept. 2. They are employees of Turkey’s Nurol Holding construction firm.

Political kidnappings and abductions for ransom take place frequently in the Iraqi capital. This week, unknown gunmen abducted Iraq’s acting deputy justice minister from his car on a Baghdad street in broad daylight.

The Death Squads militants in the video accused Turkish President Recep Tayyip Erdogan of “aggressive behavior” in the region.

“Erdogan must correct his policy, because we are people who want to live in peace,” one of the hostages said.

If Turkey’s government does not respond, “we will crush Turkish interests and their agents in Iraq with the most violent means,” a statement shown in the video said.

Turkey has faced harsh criticism for backing armed Sunni extremists in Syria. And the gunmen in the video blamed Turkey for a Sunni rebel siege on the predominantly Shiite villages of Foua and Kfarya in Syria’s northwest.

Syrian troops and fighters from Lebanon’s Hezbollah movement are fending off that assault. Iraq’s Shiite militias also have fought for the Syrian government, whose president and key military leaders belong to the Shiite-linked Alawite sect.

“Direct your militias to lift the siege . . . and allow for necessities to reach these two towns,” the video said.

In Iraq, Shiite militias that mobilized to help the army fight the Islamic State now command considerable military and political influence.

“I joined [the militias] to defend our country and our faith” from the Islamic State, said 25-year-old Haidar, a former volunteer with the paramilitary forces who is now a software engineer. “But I realized that they are at the core of the political problems in this country. And we are fighting a lost cause.”

Hugh Naylor in Beirut and Mustafa Salim in Baghdad contributed to this report.