WASHINGTON » A 3-year study by the Pentagon has concluded that U.S. intelligence agencies are "not yet organized or fully equipped" to detect when foreign powers are developing nuclear weapons or ramping up their existing arsenals. It calls for using some of the same techniques that the National Security Agency has developed against terrorists.

The study, a 100-page report by the Defense Science Board, argues that the detection abilities needed in cases like Iran’s — including finding "undeclared facilities and/or covert operations" — are "either inadequate, or more often, do not exist."

The report is circulating two months before President Barack Obama will attend his third nuclear security summit, set for March in The Hague, an effort he began in order to lock down loose nuclear materials and, eventually, reduce the number of countries that could build nuclear weapons. Obama’s efforts to sweep up the materials have largely been considered a success. But the report concluded that potential new nuclear states are "emerging in numbers not seen since the early days of the Cold War" and that "monitoring for proliferation should be a top national security objective – but one for which the nation is not yet organized or fully equipped to address."

The report confirmed what many outside experts have learned anecdotally: While the most famous intelligence failure in the past decade involving nuclear weapons occurred in Iraq, where the CIA and others saw a program that did not exist, the bigger concern may be that major nuclear programs were entirely missed.

U.S. officials first learned of a reactor in Syria, built with North Korean assistance, when the Israelis alerted them. (Israel destroyed the facility in 2007.) Early during the Obama administration, North Korea built a uranium enrichment facility that went undetected until the North showed it off to a visiting Stanford professor.

"The lesson from this history is that we found these at the last moment, if we found them at all," said Bruce Riedel, a former CIA expert on terrorism and nuclear proliferation who is at the Brookings Institution.

The Defense Science Board came to a similar conclusion. It said that in the future, satellite photographs and other reconnaissance will most likely be of limited use. Instead, it suggested that many of the cyber and big-data programs developed by the NSA should be used to detect proliferation among scientists and engineers, a bet that the United States would be more likely to pick up evidence of their talking, emailing or searching for nuclear-related technologies than it would be to see a weapons facility being built.

The growing need to detect proliferation was one of the arguments Obama made last Friday in his speech explaining why many of the programs started by the NSA in recent years must be preserved.

A former senior intelligence official familiar with the report, which was commissioned by Ashton B. Carter, the former deputy secretary of defense who resigned late last year, said the effort was to focus the government’s efforts on the global dimensions of the atomic threat.

"One of the highest priorities of successive administrations is countering proliferation," the official said. "But there’s little coherence on what agencies do to move that interest forward."

The range of government departments that were interviewed by the Defense Science Board underscores how spread out the effort has become: Officials of several of the nation’s 16 intelligence agencies participated, along with four of the Energy Department’s National Laboratories and its National Nuclear Security Administration, the Department of Homeland Security, the Defense Threat Reduction Agency and the White House’s National Security Council.

The former senior official said that many signs of a nuclear program can be found by monitoring open sources — and that clues there are frequently overlooked.

"There’s always evidence of it," he said of clandestine nuclear activity, speaking on the condition of anonymity. For instance, he said, how much of a country’s gross domestic product is devoted to certain industries could be a significant clue.

"From open sources you can put that together," he said. "But no entity in the government brings coherence to all these things."

The report did not name any specific countries that are under U.S. surveillance because of their current or suspected weapons programs. But it is no secret that the United States spends enormous resources tracking Pakistan’s arsenal, along with those of Russia, China, India, North Korea and Israel.

The report implicitly called into question whether administration officials should be so confident that they would detect if Iran ever violated the nuclear accord that began this week.

———

David E. Sanger and William J. Broad, New York Times