WASHINGTON, May 11 — Administration officials have briefed Congress on what they described as disturbing intelligence indicating that Russia is preparing to resume nuclear tests, even as President Bush is scheduled to meet with President Vladimir V. Putin of Russia to discuss arms control later this month, government officials said.
Selected members of the House and Senate met in small, closed sessions and were told of a new analysis by the Joint Atomic Energy Intelligence Committee, a panel that collects the views of many federal agencies on nuclear issues.
Among the members of Congress who received the briefing, the reaction ranged from alarm to skepticism. Some debated whether the intelligence report was a tactic to help clear the way for the United States to resume nuclear testing. Others were so concerned that they drafted legislation this week that would call for access to Russian nuclear sites and allow work on a new generation of American nuclear warheads.
The assessment described technical activities on a Russian island above the Arctic Circle that is the equivalent of the American nuclear test range in Nevada, officials said. The pattern of work on the island, Novaya Zemlya, matches known Russian activities in preparation for past nuclear tests, officials said.
The briefings to Congress were not the first time the American intelligence agencies had warned of activities on the island, though, and some government analysts have raised questions over the months about whether Russia may already have detonated tiny nuclear devices.
Russian officials steadfastly maintain that their nuclear weapons program remains within the constraints of the Comprehensive Test Ban Treaty. The treaty was signed by President Bill Clinton in 1996, but has not been ratified by the Senate. President Bush has said it does not adequately protect the nation's security interests, although the Bush administration continues to honor the test moratorium.
Operations to gather intelligence on the Russian nuclear program are among the most sensitive missions undertaken by the United States, and disputes over exactly what is occurring on Novaya Zemlya have divided intelligence analysts and administration officials in past years.
Officials insisted that the Congressional briefings had nothing to do with pushing a hard-line agenda ahead of Mr. Bush's meeting with Mr. Putin this month. The timing of the briefings "was coincidental," one administration official said.
One member of Congress, who was present at the briefing and remained skeptical of the evidence of Russian testing, said, "The administration seems to want to resume nuclear testing and to develop new nuclear weapons."
The only public reference to the briefings came on the floor of the House on Thursday, when Representative Curt Weldon, Republican of Pennsylvania, made passing reference to the intelligence analysis. Mr. Weldon said the briefing he attended was at the "code word level" of classification, and he said he was so alarmed that he drafted an amendment to the 2003 defense authorization bill.
The version of his amendment that passed the House this week would allow the United States to conduct research and conceptual design work on a new class of nuclear warheads. Language was deleted that would allow the United States to resume testing if the government certified that another nation had resumed testing. But in setting up what Mr. Weldon called "an aggressive level of transparency," the amendment would establish a program for Russian scientists to visit the Nevada nuclear test site in exchange for visits by Americans to Novaya Zemlya.
"There may be something going on in Russia that we don't understand, that may trouble us — and they may feel the same about something we're doing on our side," Mr. Weldon said in a telephone interview after the vote. "It's best to counter that, and not to recreate feelings that existed in the cold war, but take this opportunity to engage."
Mr. Weldon, who described himself as "Russia's best friend but her toughest critic," said he remained deeply concerned that conservative elements in Russia's Defense Ministry, its foreign intelligence service and its atomic energy ministry "want to move us and Russia away from a close dialogue" and might be responsible for the worrisome actions at Novaya Zemlya.
Sean McCormack, spokesman for the National Security Council, said today that the White House would have no comment on intelligence matters. On the question of Russian nuclear testing, he said, "We are concerned that we may not be able to know if any entity were testing in a way designed to avoid detection, and we expect Russia to abide by the testing moratorium it has declared for itself."
The intelligence report on Novaya Zemlya was included in a broader briefing to Congress on cooperative programs between the United States and Russia to reduce threats from nuclear, biological and chemical weapons, a project that includes tracking Moscow's compliance with a number of arms control agreements, including the test-ban treaty.
When internal administration debates over Russian nuclear testing surfaced previously, just more than a year ago, the director of nuclear weapons development and testing at the Russian atomic energy ministry denied any violation of the comprehensive test ban, a stance repeated by a variety of Russian officials in the intervening months.
In an interview in February 2001 with The New York Times, Dr. Nikolai P. Voloshin said that work at Novaya Zemlya was to ensure the reliability of aging warheads, not to develop new weapons. He noted that the test-ban treaty defined no specific "threshold" for a violation, but said simply that nuclear explosions should not occur. "It doesn't specify whether one neutron or two neutrons can be emitted," he said.
Advocates of the test-ban treaty pointed out that it had provisions under which the United States could seek to inspect the Russian test site, and they expressed concerns that the briefings for Congress were part of an administration campaign to resume nuclear tests in Nevada.
"The Bush administration appears to be slowly but steadily moving in the direction of removing the obstacles preventing a resumption of U.S. testing and developing a rationale for resuming testing," said Daryl G. Kimball, executive director of the Arms Control Association. "While it is clear that this administration has no interest in seeking ratification, it must be careful not to provoke other nuclear states and further alienate allies who support the test ban treaty."
The administration's recent assessment of the nation's strategic arsenal, called the Nuclear Posture Review, suggests it may be necessary to resume testing to make new nuclear weapons and to ensure the reliability of existing ones.
The Bush administration has no formal plans to resume nuclear testing, but the president has said he does not support the Comprehensive Test Ban Treaty, describing it as not verifiable and not enforceable.
Mr. McCormack, the National Security Council spokesman, today repeated administration policy that "the United States has no plans to resume its nuclear testing program." He emphasized that the administration would "continue to observe the nuclear testing moratorium consistent with our right to take measures to ensure stockpile safety and integrity in extraordinary circumstances."
Officials at the Departments of Defense, Energy and State, and at the National Security Council have discussed whether President Bush should renounce Mr. Clinton's signature on the test-ban treaty. Just this week, the Bush administration formally renounced American support for the treaty creating an International Criminal Court; that treaty likewise had been signed by Mr. Clinton but was not ratified by the Senate.