A prestigious medical journal tightened security Thursday after an anti-abortion group branded as "Nazi-like" a published study on two widely available drugs that can be used to perform abortions.

Randall Terry, an activist from Operation Rescue, sent a fax Thursday to the New England Journal of Medicine railing against the study, published in Thursday's issue, which could transform abortion practices in the United States by enabling women to have abortions without surgery.

The study, written by Dr. Richard Hausknecht of the Mt. Sinai School of Medicine in New York, found that a common anti-cancer drug combined with an anti-ulcer medicine induces abortions in women in the early stages of pregnancy.