An angry crowd prevented Cuba's unofficial human rights group from holding a news conference, the first such incident in months of apparent official tolerance of such dissidents. The meeting in Havana was called by the Cuban Human Rights Committee and attended by a handful of foreign journalists at a private house. It was noisily interrupted by 100 people shouting "Viva Fidel (Castro)!" The group was led by a man identified as the head of the local Committee for the Defense of the Revolution. As scuffles broke out, police arrived at the scene, but after 2 1/2 hours of negotiations, during which the shouting crowd grew to more than 500, dissident Ricardo Bofill and other rights activists were allowed to leave under police escort.