The operation led to a serious eight-day military engagement between ONUC and the Katangese forces. Tshombe's paid mercenaries were prepared for the UN forces and launched an effective counterattack. Seven UN troops were killed as well as 200 Katangese civilians and troops. Operation Morthor was executed with Indian support, but without full approval by several member countries of the UN, particularly the UK, France, and United States. The Soviet Union was angrily accusing the US of supporting the assassination of Lumumba, a Soviet ally, and of installing American ally Mobutu as president. The Soviet state interpreted ONUC to now be acting as a proxy for the US rather than supporting the interests of the entire Security Council.