U.S. congressional hearings over the past several weeks have shown that the Bush administration's plan to move ahead with a new generation of nuclear warheads faces strong opposition from House and Senate members concerned that the effort lacks any strategic underpinning and could lead to a new nuclear arms race, The Washington Post reported Sunday.

Experts inside and outside the government questioned moving forward with a new warhead as old ones are being refurbished and before developing bipartisan agreement on how many warheads would be needed at the end of what could be a 30-year process. Several, including former senator Sam Nunn, suggested linking production of a new warhead with U.S. ratification of the Comprehensive Test Ban Treaty, a move the Bush administration has opposed.

Representative David L. Hobson, a Republican from Ohio, who originated what has become the Reliable Replacement Warhead (RRW) program, wants the number of warheads in the current U.S. stockpile declassified as "the first step for an honest dialogue on nuclear weapons."

Including warheads that are deployed, inactive and in reserve, the total is assumed to be above 6,000, according to the report.

The program involves not only coordinating the design and costs of a new warhead for the Trident submarine-launched intercontinental missile, but also a multibillion-dollar plan -- called Complex 2030 by the Department of Energy -- to modernize the aging nuclear weapons facilities where warheads and bombs are designed, built and dismantled.

At a House hearing late last month, Nunn, a former chairman of the Senate Armed Services Committee, said he does not favor dismantling the U.S. nuclear arsenal, but he expressed concern about the international impact of the RRW program.

Former defense secretary William J. Perry said at the hearing that development of the RRW program "will substantially undermine our ability to lead the international community in the fight against proliferation, which we are already in danger of losing."

Senator Byron Dorgan, chairman of the Senate Appropriations Subcommittee that funds the nuclear weapons complex, said playing a major role in funding the nation's nuclear weapons poses important questions for him, and he is unsure how he will come out on the program.

There are "serious questions to answer," he said. "The survival of this planet, I think, depends on our getting these things right."