WASHINGTON: The Bush administration is reassessing America’s nuclear arsenal with an eye toward smaller bombs to combat 21st century perils but arms control advocates worry Washington wants to lower the threshold for using nuclear weapons.

“They are seeking to make these weapons more usable and are thinking about these as just another kind of weapon in our arsenal,” said Daryl Kimball, executive director of the Arms Control Association.

“And that kind of thinking is dangerous. It promotes proliferation. And it’s unnecessary given our overwhelming conventional superiority. This is the classic case of capability overkill.”

The Pentagon says it is aiming to modernize a Cold War arsenal to meet 21st century threats.

Defence Secretary Donald Rumsfeld has argued that potential adversaries, knowing US precision weapons can hit almost any target at any time, are seeking to make military assets invulnerable by burying them deep underground, including facilities to make and store chemical and biological arms.

Pentagon leaders say nuclear weapons may provide an effective way to destroy such bunkers and wipe out enemy stocks of chemical poisons and disease-spreading biological agents.

During the Cold War, the vast Soviet nuclear arsenal was deemed the prime threat to America.

The Pentagon, in a statement explaining US nuclear policy, said the new threat is posed by what it calls rogue states and terrorist groups armed with weapons of mass destruction.

“We need a wider range of capabilities and options to assure our friends as well as potential enemies of the US that we have the resolve and the ability to carry out our national security policy and strategy,” the statement added.

The administration won congressional backing in May for measures that would allow studies on new low-yield nuclear weapons and the conversion of two existing high-yield nuclear bombs for use against deeply buried targets.—Reuters