Gunmen kidnapped 18 Turkish workers Wednesday in Iraq's capital.
The workers, who were part of a crew building a football stadium, were taken in the mainly Shi'ite Habibiya district in northeastern Baghdad.
There was no indication of the identity of the kidnappers or their motive.
Turkey's Deputy Prime Minister Numan Kurtulmus said Turkish authorities were in contact with those in Iraq.
Last year, Islamic State militants seized 49 Turkish hostages from Turkey's consulate in Mosul and held them for more than three months before releasing the group. Those hostages included diplomats, soldiers and children.