On 5 June 1997, anticipating a Sassou-led coup, Lissouba ordered the Cocoye militia to detain Sassou and forcibly disarm the Cobra militia, thus initiating a second civil war. Fighting soon engulfed the whole city, with the Cobra, Cocoye and Ninja militias each controlling areas within the capital. The government recruited Ukrainian mercenaries to fly attack helicopters, later mobilizing them in a bombing campaign of Cobra-controlled areas. Both sides actively shelled densely populated areas, causing a high civilian death toll. Combatants engaged in numerous instances of extortion and harassment of the civilian population, selecting their targets on the basis of ethnicity.