Islamic State militants struck at Kurdish forces southwest of the Iraqi city of Kirkuk on Friday morning, while bombs in Baghdad and Samarra killed at least 21 people, security and medical sources said. Police in the northern province of Kirkuk said Islamic State launched mortars and attacked positions of Kurdish peshmerga fighters in four districts southwest of Kirkuk city. Islamic State has frequently battled Iraqi security forces and Shi'ite militias further south and west since the radical jihadist group surged across the Syrian border last summer, but attacks on the outskirts of Kurdish-controlled Kirkuk have been less frequent. A peshmerga officer told Reuters his forces had recaptured the district of Mariam Bek but said clashes were ongoing in Tal al-Ward, Maktab Khalid and Mullah Abdullah.