The experiment is intended to speed the development of tests to detect the smallpox virus and of drugs that could treat it. The action was prompted in part by concerns that the disease could be reintroduced to the public, either accidentally or through terrorism.

A spokesman said process involves the insertion of a marker gene into the virus that would glow under fluorescent light when the virus was exposed to an ineffective drug.

The experiment, one of several proposals Friday regarding smallpox, is intended to speed the development of tests to detect the virus and of drugs that could treat it, the New York Times reported Saturday. The action was prompted in part by concerns that the virus could be reintroduced to the public, either accidentally or through terrorism.

The tests would be the first since the disease was eradicated from the world 25 years ago.

The organization's governing body, the World Health Assembly, also said Friday it was in favor of sending small fragments of the smallpox virus to other laboratories to develop better diagnostic tests for the virus.

However, it said scientists would be required to provide details about the experiments and planned security precautions before they could proceed.