WASHINGTON (AP) _ Prompted by fears that terrorists might get their hands on the world's last remaining smallpox virus, U.S. scientists are preparing to seek new treatments for the disease eradicated a generation ago.

The only smallpox known to remain in the world is held under tight security at research labs in Atlanta and Siberia. Scientists are fighting to have the virus destroyed, but the World Health Organization has postponed that execution indefinitely.

Scientists from the Defense Department and federal health agencies met here Friday to begin figuring out how to revive research on smallpox until the WHO again tackles the issue.

They tentatively agreed that a top priority should be testing whether new antiviral drugs kill smallpox, said Dr. D.A. Henderson of the Department of Health and Human Services.

``By the end of June, we'll have a pretty well laid-out plan,'' said Henderson, who headed the 10-year global effort to eradicate smallpox.

Fears about terrorist use of smallpox arose after Moscow's 1993 civil uprising, when fighting occurred near the poorly controlled lab that housed the smallpox. Russia then quietly moved the virus to a better lab in remote Novosibirsk.

Moves to revive smallpox research were strengthened after the Tokyo subway gassing. Henderson said there is no way to be positive no other smallpox stocks exist or that a smallpox-like disease couldn't be engineered from a relative virus.

Friday's meeting was the scientists' first in deciding what smallpox research should be done. Among the decisions remaining is whether the research will be performed by the Centers for Disease Control and Prevention, which now houses the only smallpox virus in the United States, or by the Army's top viral lab in suburban Washington.