 Soviet troops occupied the cities and main arteries of communication, while the mujahideen waged guerrilla war in small groups operating in the almost 80 percent of the country that was outside government and Soviet control, almost exclusively being the rugged, mountainous terrain of the countryside.The Soviets used their air power to deal harshly with both rebels and civilians, levelling villages to deny safe haven to the mujahideen, destroying vital irrigation ditches, and laying millions of land mines.The international community imposed numerous sanctions and embargoes against the Soviet Union, and the U.S. led a boycott of the 1980 Summer Olympics held in Moscow.