The top Shiite cleric in Iraq has called for the release of 18 Turkish workers kidnapped in Baghdad last week.

Grand Ayatollah Ali al-Sistani's statement, issued Saturday, came a day after a video released by a shadowy militant group showed the captives, who were snatched up from a construction site in Baghdad's Shiite-dominated Sadr City. The group's name and slogan suggest it is Shiite.

The influential cleric denounced the kidnapping as "unethical, illegitimate and illegal."

The group in the video demanded Turkey halt the flow of militants into Iraq, lift a "siege" on Syrian Shiite cities and stop the passage of oil from Iraq's northern Kurdish region via Turkey in defiance of Baghdad.