South Korea and the United States began the Hoguk exercise which they did every year. The Hoguk exercise was a large military practice with both South Korean and US militaries. The 2010 exercise used 70,000 soldiers from all four kinds of the South Korean military. They had 600 land vehicles, 90 helicopters, 50 warships, and 500 aircraft. The North Korean government felt that these exercises were a preparation for attacking the North, though the South and US said it was not.