Up to 3,000 fleeing Iraqis 'captured by Islamic State'
Twelve of the captives were executed by the militant group and six burnt.
The internally displaced civilians were trying to flee to the city of Kirkuk from villages in the Hawiga district before being captured on August 4.
"Daesh captured thousands of people who tried to escape Hawiga at night," a local source told The New Arab, using the Arabic acronym for the Islamic State group.
The Iraqi Observatory for Human Rights has called on the Iraqi government and the UN to do their part in ending the crisis and freeing the captives.
The oil-rich Kirkuk province is divided between areas controlled by the Kurds and the Islamic State group.
The militant group overran large areas north and west of Baghdad in 2014, but Iraqi forces have since regained significant ground and are conducting operations to set the stage for the battle to recapture Mosul, the last IS-held city in the country.
The militants have responded to the battlefield setbacks by striking civilians, and experts have warned there may be more such attacks as the extremists continue to lose ground.
Earlier this week, the UN's Assistance Mission for Iraq [UNAMI] said that a total of 629 Iraqi civilians were killed and 1,061 were injured in acts of terrorism and armed conflict in Iraq, excluding Anbar province, in July.
Another 130 members of the Iraqi military, including Peshmerga and allied militias, were killed and 146 were injured.
Iraq descended into civil war and unrest shortly after the disastrous Anglo-American invasion of Iraq in 2003. Hundreds of thousands of Iraqis, mostly civilians, have been killed since.