In the 1960's, the Italian Communist Party's gradual shift towards the center and its policy of collaboration with the Christian Democrats worried conservative forces on the one hand and angered leftist militants on the other hand. On December 12, 1969, a bomb exploded in front of the Bank of Agriculture in Milan, killing 16 people and wounding 90. Other bombs were exploded elsewhere in the country. It was the strategy of the extreme right intended to create chaos and an erosion of confidence in existing institutions which would facilitate the establishment of a rightist government. Leftist groups, on the other hand, began to organize and prepare themselves to fight an underground battle in the event the right succeeded in gaining power or Communist Party compromises with the Christian Democrats continued. Until 1975, the only active leftist guerillas were the Red Brigades and the Armed Proletarian Nuclei. New groups emerged in 1976, and although none of them had the continuity and effectiveness of the other two, their appearance did indicate the spread of the urban guerilla movement. In 1977, a wave of protest shook Italian universities, largely resulting from runaway inflation and unemployment which had brought the country to the verge of bankruptcy. General disillusionment with and hostility toward the existing political and socioeconomic system was spreading. It has been estimated that about 1,000 people are involved in underground urban guerilla activities, and supporters may number between 3,000 and 8,000. Sympathizers have been estimated at 200-300,000. Significant government action that can bring economic relief and rally citizens to the support of reforms appears to the the only hope for stemming the tide of growing violence.