The new weapon would not add to but replace the nation's existing arsenal of aging warheads, with a new generation meant to be sturdier, more reliable, safer from accidental detonation and more secure from theft by terrorists, the report said.

The announcement, to be made by the interagency Nuclear Weapons Council, avoids making a choice between the two designs for a new weapon, called the Reliable Replacement Warhead, which at first would be mounted on submarine-launched missiles, The Times said.

The effort, if approved by President George W. Bush and financed by Congress, would require a huge refurbishment of the nation's complex for nuclear design and manufacturing, with the overall bill estimated at more than 100 billion dollars, the report said.

But the council's decision also raises the question of whether the United States will ultimately be forced to end its moratorium on underground nuclear testing to make sure the new design works, The Times pointed out.

On Friday, Bryan Wilkes, a spokesman for the National Nuclear Security Administration of the Energy Department, said the government would not proceed with the Reliable Replacement Warhead "if it is determined that testing is needed," the paper said.

But other officials in the administration, including Robert Joseph, the under secretary of state for arms control and international security, have said that the White House should make no commitment on testing, according to the report.

If Bush decides to deploy the new design, he could touch off a debate in a Democrat-controlled Congress and among allies and adversaries abroad, who have opposed efforts to modernize the arsenal in the past, The Times said.

At a time when the administration is trying to convince the world to impose sanctions on North Korea and Iran to halt their nuclear programs, critics argue, any move to improve the US arsenal will be seen as hypocritical, the paper pointed out.

Related Links
Learn about nuclear weapons doctrine and defense at SpaceWar.com