On 3 January 2020, the revolutionary guard's general, Qasem Soleimani, was assassinated by the United States in Iraq, which considerably heightened the existing tensions between the two countries. Three days after, Iran's Islamic Revolutionary Guard Corps launched a retaliatory attack on US forces in Iraq and shot down Ukraine International Airlines Flight 752, killing 176 civilians and leading to nation-wide protests. An international investigation led to the government admitting to the shootdown of the plane by a surface-to-air missile after three days of denial, calling it a "human error".