article_snippet: An injured Iraqi officer waits for treatment on the front line during clashes with Islamic State extremists in Tikrit on March 31 .
article_snippet: Prime Minister Haider al-Abadi ' was referring to paramilitary groups which played a major role in the fighting to retake Tikrit, a Sunni Arab city which ISIS had controlled since ISIS captured swathes of Iraq in June last year.
article_snippet: Iraqi army and police forces, as well as volunteers and Iran-backed Shiite militias, completely surrounded Tikrit within two weeks of launching the operation.
article_snippet: Smoke rises from central Tikrit during clashes between Iraqi security forces and Islamic State extremists on March 31 .
article_snippet: American jets began bombing ISIS targets in central Tikrit on March 25.
article_snippet: The move sparked a freeze in the participation of the Popular Mobilisation units, an umbrella organisation for volunteers and militias which accounted for the bulk of the manpower involved in the Tikrit battle.
article_snippet: Iraqi security forces take up a position as Iraqi security forces fight Islamic State militants in the city of Tikrit in Iraq on March 31 .
article_snippet: But after giving the Iraqi tricolour political cover by declaring that the Iraqi tricolour do not want to work with each other, both sides took part in the Tikrit operation this week.
article_snippet: Iraqi government forces keep watch from a position on the southern outskirts of Tikrit on March 30 .