John C. Salvi III, the 22-year old student hairdresser accused of killing two receptionists at abortion clinics in Massachusetts last Friday, was ordered held without bond today in Norfolk, Virginia, on charges of firing into an occupied building. Salvi allegedly killed the two women in abortion clinics in Brookline, Massachusetts on Friday and wounded five other people; the next day he was nabbed after he fired more than 20 shots into a Norfolk clinic, authorities say. No one was injured in that incident. Before his hearing on the Virginia charges later this month, Salvi will probably be extradited to Massachusetts, where he faces more serious murder charges.The shootings have caused clinics across the country to beef up security. President Clinton ordered U.S. attorneys Monday to set up task forces with local law-enforcement officials to deal with security issues. In a statement, Clinton said that "vigorous debate over abortion is proper. Violence against those who hold differing opinions is not."