The United States urged the world Thursday to follow its lead in renouncing the use of chemical weapons.

Chief U.S. delegate Stephen Ledogar told the Geneva Conference on Disarmament that action by other countries would speed progress toward ending the specter of toxic warfare."We call upon all states to declare their chemical weapons stocks and to forswear the use of CW (chemical weapons) for any reason when the CWC (Chemical Weapons Convention) enters into force," he said.

The 40-nation conference, which covers a wide range of mass-destruction arms, resumed work on chemical weapons Thursday after a three-month recess.

The new session began four days after President Bush announced fresh U.S. concessions to speed up completion of a treaty banning possession and stockpiling of chemical weapons, often dubbed "the poor man's atom bomb" because they are easy to manufacture.

Their use is outlawed by a 1925 treaty, although Iraq has dropped chemical weapons on its own Kurdish population and in its conflict with Iran.

It did not use its toxic arsenal in the gulf war, possibly for fear of retaliation by the United States, which did not rule out that possibility.

Bush said Monday the United States would not use toxic arms, even to retaliate in kind.

He also said the United States was ready to destroy its stockpile of toxic arms within 10 years of a treaty coming into force and that Washington was dropping previous insistence on keeping a small amount of such weapons until all countries had joined the treaty.

In addition to the United States and the Soviet Union, at least 15 countries have chemical weapons.