Roxham Road was barricaded in both directions at the border in the 1970s. The U.S. Border Patrol had begun putting gates up at some unguarded crossings along the land border in New York and Vermont to inhibit smuggling early in the decade. Canada barricaded all uncontrolled crossings on its side as part of security operations supporting the 1976 Summer Olympics, fearful that terrorists like those who had killed Israeli athletes at the 1972 Munich Olympics could do something similar in Montreal, where the Games were held, and then quickly escape across the border. During the 1980s, when illegal migration primarily took place from Canada into the U.S., the Border Patrol augmented this with electronic surveillance equipment.