WASHINGTON (AP) _ A scientist found to be testing human embryos for genetic flaws during an off-duty private research project was cut off from support by the National Institutes of Health.

Officials took the action after deciding that the embryo gene testing might violate a federal ban on experimenting with human embryos.

An NIH spokeswoman said federal research contracts with Dr. Mark R. Hughes of Georgetown University were ended in October after the NIH found he was conducting the embryo gene studies for a private fertility clinic at a nearby hospital.

Though Hughes was not a federal employee, spokeswoman Ann Thomas said that he was conducting research on cell biology at NIH under a contract between the agency and Georgetown University.

She said officials learned that he also was using NIH equipment and worked with NIH scientists in the embryo studies at the hospital.

Hughes said Thursday that the work never involved whole human embryos. He said he was analyzing DNA extracted from a cell taken from embryos that had been developed in a private fertility practice, the Montgomery Fertility Institute.

He said the results of his DNA analysis were used to identify embryos that carried inheritable disorders. This allowed doctors at the fertility institute to select the healthiest embryos for implantation.

Hughes said his work did not genetically alter the embryos or otherwise change them.

The researcher also said he was not actually kicked off the NIH campus, but that he left after a contract expired in October. He continues to do research at Georgetown University.

Thomas said that Hughes was assisted in the DNA analysis by six NIH ``research associates,'' who were post-doctoral students employed by NIH. She said that associates are required to get permission before doing such outside work, but that this was not done.

Three of the associates now work for Hughes at Georgetown University. Another works at another university and two others returned to NIH.

Thomas also said that Hughes used NIH equipment, including two refrigerators, that had been assigned to Georgetown University under terms of a research contract. That equipment has now been removed from the hospital and installed at Georgetown, Hughes said.

Hughes said NIH officials were aware of his work for the fertility institute because he gave seminars on the research at NIH meetings.

Dr. Jay Grodin, a doctor at the Montgomery Fertility Institute, said Hughes did the genetic research for couples who were carriers of genetic disease and were fearful that their children would inherit the disorders.

Grodin said Hughes was not paid for the work, nor were patients charged extra for the studies.

``The DNA work helped us to select the right embryos,'' said Grodin. ``It was done as a noble attempt to help. This guy was just trying to do good.''

A number of the embryos analyzed by Hughes were implanted, said Grodin, but none resulted in live births.