Islamic State (IS) militants beheaded five Peshmerga fighters in the city of Mosul, south of Iraq, the German Press Agency (DPA) reported Sunday. Kurdish Peshmerga sources, who asked to remain anonymous, told the press agency that IS militants had beheaded, late Saturday, five Kurdish fighters who were held hostage. The execution took place in front of dozens of Mosul residents, cancelling the Kurdish new year celebrations. The sources added that the bodies were transferred to the morgue in Mosul. Meanwhile, foreign fighters have voluntarily joined the Kurdish Peshmerga forces to fight against IS in combat areas, which extend from the northwest to the south of Kirkuk city, according to two Kurdish Peshmerga officers. Kurdish Peshmerga Lt. Col. Luqman Mohamed told DPA that 20 foreign fighters had joined the Peshmerga ranks coming from different countries, mainly the United States, and that most of them had combat experience. Mohamed said that their presence is necessary to give advice and pass on their expertise to the Kurdish fighters in order to achieve victory against IS, adding that the foreign fighters are always present at Peshmerga headquarters in Kirkuk and combat areas. Commander of Peshmerga operations in south of Kirkuk, Westa Rasoul also explained that the presence of foreign fighters within the Kurdish forces' ranks was very important, as they took part Saturday in assaults on IS' sites. Rasoul clarified that they were backed by the international coalition fighter jets and that part of their role was to organize plans to achieve victory against IS. Peshmerga forces in Kirkuk have more than seven thousand fighters and so far almost 300 have died and more than 2500 were wounded, since June 10.