BAGHDAD, Feb. 8 (Xinhua) -- Islamic State (IS) militants on Friday executed three brothers kidnapped one day before in Iraq's northern central province of Salahudin, local media source said.

"Three brothers were kidnapped by IS on Thursday from north of Baiji, some 220 km north of Iraq's capital Baghdad, and later were executed on Friday," Jamal al-Dulaimi, media director of Salahudin province, told Xinhua.

"The bodies were found dumped near the Makhoul mountain area with gunshot wounds in the back, and then the bodies were taken to the forensic medicine department," al-Dulaimi added.

The three victims were brothers from al-Messhag village, located north of Baiji, and were kidnapped on a trip collecting truffles.

In December 2017, Iraq declared full liberation from the IS after the security forces and the paramilitary Hashd Shaabi units, backed by the anti-IS international coalition, recaptured all areas once seized by the extremist group.

However, IS remnants have since melted in urban areas or resorted to deserts and rugged areas as safe havens, carrying out guerilla attacks from time to time against the security forces and civilians.