the corps was battered by the u.s. task force viking (cjsotf-north) during the 2003 invasion of iraq. among other actions, u.s.-led forces seized kirkuk. the successful occupation of kirkuk came as a result of approximately two weeks of fighting that included the battle of the green line (the unofficial border of the kurdish autonomous zone) and the subsequent battle of kani domlan ridge (the ridgeline running northwest to southeast of kirkuk), the latter fought exclusively by 3rd battalion, 10th sfg and kurdish peshmerga against the 1st corps.