WASHINGTON — A confidential government report obtained by Al Jazeera’s Investigative Unit sharply criticizes the U.S. Department of State’s diplomatic security operations and raises serious concerns about an elaborate embassy construction program overseas.

The report, prepared by a six-member panel of veteran security and foreign service experts, said the department’s most important security arm, the Bureau of Diplomatic Security (DS), operates much like a lone wolf. The panel said that DS, also referred to as the Diplomatic Security Service, often withholds vital information from other department bureaus concerned with the security of overseas personnel.

"Some of this is attributed to ‘law enforcement sensitive’ issues," the panel wrote, "but other security information that enhances understanding, cooperation, and coordination should be widely disseminated in a timely way." DS as an organization, the panel said, "has not always been quick to adapt, or been innovative in dealing with overarching strategic foreign policy issues. The culture must be modified."

The panel, created by the State Department in the aftermath of the attack on the special mission in Benghazi, Libya, in September 2012, said the State Department must get its act together or face serious consequences. Referring to previous attacks on U.S. missions, the panel members wrote, "Delay and denial are not options. There will be a next Nairobi, or a Benghazi, and DS and its Department partners must do everything to be ready. Lives are at stake."

The panel also delivered a stiff jab to another State Department entity, the Bureau of Overseas Buildings Operations (OBO), which supervises the design and construction of U.S. facilities abroad. The bureau is pushing a new design and building program that, department officials said, enhances the appearance of overseas facilities but also provides essential security for the safety of U.S. personnel.

But, the panel saw things differently. Headed by Grant S. Green Jr., a former under secretary of state for management in the administration of President George W. Bush, the panel said that the new design program would likely increase the risks for overseas U.S. personnel. Fewer embassies would be built and design and construction of new facilities would take longer, the panel said, "leaving more personnel exposed in inadequate facilities for longer periods of time."

In an interview, Green said that security personnel and others interviewed by his panel expressed serious reservations about the design program and its costs. As a result, he said, the panel recommended that the department undertake "a detailed review of the security implications" of the design approach. Green said, "I don’t think the department did any kind of study the way I would define a study."

In an email, a department spokesman said officials revisited the security issues highlighted by the panel and found that "concerns raised over the timeframe were not a substantial concern." The new design approach, he said, "had significant potential" to shorten the time it takes to build an embassy. "Security has been and remains the primary component" of the department’s design initiative, he added.

The new program, Design Excellence, has drawn scrutiny in other government quarters, according to people familiar with the reviews. Investigators in the U.S. Congress are reviewing the program, focused on costs and safety issues related to the glass-cubed $1 billion showplace embassy being built in London and another embassy under development in Port Moresby, Papua New Guinea. Separately, State Department Inspector General Steve Linick’s staff began auditing the costs of the London embassy in February.

Within the State Department, several managers in the Bureau of Overseas Buildings Operations, concerned about the focus on Design Excellence, retired recently. They include the former director of OBO’s design and engineering office, according to several people familiar with the retirements.

The Green report on diplomatic security organization and management grew out of the attack on the Benghazi mission that killed Ambassador J. Christopher Stevens and three other Americans. The attack has prompted a firestorm of criticism directed at U.S. diplomatic officials and led to several internal and congressional investigations.

Not long after the attack, the State Department established an accountability review board, or ARB, to investigate what happened in Benghazi. The ARB, headed by retired Ambassador Thomas R. Pickering, issued a report detailing State Department’s security lapses and recommended that two other panels be convened — one to review high-threat diplomatic missions around the world, the other to report on diplomatic security organization and management. Green, who oversaw the diplomatic security operation as Under Secretary for Management, was named by the State Department to chair the organization and management review.

The State Department has kept both Green’s report and the high-threat review under wraps. The high-threat report became public only after Al Jazeera’s Investigative Unit published the report in September. Green’s 41-page report was delivered to Patrick Kennedy, under secretary of state for management, last May. Department officials stamped it "sensitive but unclassified."

Asked why the Green report’s critical review of diplomatic security was not released, the State Department spokesman described it as an "internal" document that contained "information regarding the department’s internal security procedures." He said the department is implementing 30 of the 35 recommendations contained in the report.

At the center of criticism in Green’s report is DS, the State Department’s diplomatic security and law enforcement agency that protects Secretary of State John Kerry, foreign dignitaries who visit the U.S., and American personnel and facilities overseas.

The panel delivered some tough medicine. The complexity of the diplomatic security mission, the panel said, has "overwhelmed" the ability of the department "to conduct coordinated operations in the most effective and efficient way." The department "must improve its organizational approach to security" to maximize security for all employees, the panel said, "including the ways in which security-related information is obtained, disseminated, and coordinated across the department."

Citing the attack against Benghazi and violence directed at other U.S. missions, the panel said effective physical security and coordination of security information were central to mitigating risks, particularly in dangerous overseas locations. Yet, the panel said, the Bureau of Diplomatic Security often refuses to share information with other State Department bureaus. It said:

Probably the most troubling to the panel was the impression that DS personnel do not think of their organization as an integrated partner with others in the Department. They instead see themselves as a law enforcement organization with loyalty first and foremost to DS rather than the Department.

Morale was yet another problem. Many in DS, the report said, "feel they were made the scapegoat" for the Benghazi management debacle. Several diplomatic security employees expressed concern that the next security crisis "may result in other DS personnel being singled out for punishment."

Within Diplomatic Security, the panel noted, there is a feeling of isolation and a lack of understanding of what other State Department bureaus are up to. The panel explained:

A recurring theme in panel interviews with both DS and other Department personnel is the sense that DS is becoming increasingly isolated from the overseas-oriented culture of the Department and more focused on its law enforcement and para-military functions. As a result, DS personnel do not fully understand what the rest of the Department is doing and why, and others in the Department do not truly understand the range of roles for which DS is responsible.

This trend, the panel said, is not surprising, given diplomatic security’s "rapid expansion in the past decade while building, literally from scratch, very robust security infrastructures for Department operations in...two war zones."

DS also is laboring under a growing workload. "As the world has become more dangerous," the panel said, diplomatic security "has had to take on additional missions and responsibilities that have outpaced even their resource increases of the past decade."

More than 100 people, many from within DS, were interviewed by panel members. Among the issues and recommendations outlined in the report: