To protest the late 1979 Soviet invasion of Afghanistan, the United States sponsored a boycott of the Summer Olympic Games in Moscow in 1980. In total, 65 countries refused to participate in the games, while 80 countries sent athletes. The only participating country by invitation was the USSR. The main reason for the boycott was the Soviet invasion of Afghanistan, which many nations viewed as an act of aggression against a friendly country. However, there were also concerns about the human rights record of the USSR and its treatment of its citizens. Additionally, some nations believed that competing in such circumstances would be inappropriate. Finally, some countries opted out because they could not afford to send a team to Moscow. In response to the boycott, the Soviet government organized a series of competitions called "Inter-Zonal" tournaments where winners went to the Olympics. Only the USSR managed to qualify for both types of tournament - Zonal and Inter-Zonal. It is estimated that this decision cost the USSR more than $100 million dollars in lost revenue. The US government had been pressuring Canada and Mexico not to participate in the games, but both countries stood firm on their decision to go to Moscow. Even so, neither Canada nor Mexico sent a delegation to the event.