Thousands of peasants, workers and students marched through this capital Friday to demand peace, an end to military impunity and a purge of the armed forces.

The march, in which an estimated 15,000 people took part, was sponsored by the National Debate for Peace, an umbrella organization of religious, labor, social and student organizations.The demonstrators carried signs and banners demanding punishment for officers and soldiers implicated in violent acts of repression. They also chanted support for U.N.-mediated peace talks designed to end 11 years of civil war.