Updated

The U.S. government, led by the Pentagon and CIA, censored in the name of national security files that the public requested last year under the Freedom of Information Act more often than at any time since President Barack Obama took office, according to a new analysis by The Associated Press.

Overall, the Obama administration last year answered its highest number of requests so far for copies of government documents, emails, photographs and more, and it slightly reduced its backlog of requests from previous years. But it more often cited legal provisions allowing the government to keep records or parts of its records secret, especially a rule intended to protect national security.

The AP's analysis showed the government released all or portions of the information that citizens, journalists, businesses and others sought at about the same rate as the previous three years. It turned over all or parts of the records in about 65 percent of requests. It fully rejected more than one-third of requests, a slight increase over 2011, including cases when it couldn't find records, a person refused to pay for copies or the request was determined to be improper.

The government's responsiveness under the FOIA is widely viewed as a barometer of the federal offices' transparency. Under the law, citizens and foreigners can compel the government to turn over copies of federal records for zero or little cost. Anyone who seeks information through the law is generally supposed to get it unless disclosure would hurt national security, violate personal privacy or expose business secrets or confidential decision-making in certain areas.

The AP's review comes at the start of the second term for Obama, who promised during his first week in office that the nation's signature open-records law would be "administered with a clear presumption: In the face of doubt, openness prevails." The review examined figures from the largest federal departments and agencies. Sunday was the start of Sunshine Week, when news organizations promote open government and freedom of information.

White House spokesman Eric Schultz said in a statement that during the past year, the government "processed more requests, decreased the backlog, improved average processing times and disclosed more information pro-actively." Schultz said the improvements "represent the efforts of agencies across the government to meet the president's commitment to openness. While there is more work to be done, this past year demonstrates that agencies are responding to the president's call for greater transparency."

In a year of intense public interest over deadly U.S. drones, the raid that killed Usama bin Laden, terror threats and more, the government cited national security to withhold information at least 5,223 times — a jump over 4,243 such cases in 2011 and 3,805 cases in Obama's first year in office. The secretive CIA last year became even more secretive: Nearly 60 percent of 3,586 requests for files were withheld or censored for that reason last year, compared with 49 percent a year earlier.

Other federal agencies that invoked the national security exception included the Pentagon, Director of National Intelligence, NASA, Office of Management and Budget, Federal Deposit Insurance Corporation, Federal Communications Commission and the departments of Agriculture, Commerce, Energy, Homeland Security, Justice, State, Transportation, Treasury and Veterans Affairs.

U.S. courts are loath to overrule the administration whenever it cites national security. A federal judge, Colleen McMahon of New York, in January ruled against The New York Times and the American Civil Liberties Union to see records about the government's legal justification for drone attacks and other methods it has used to kill terrorism suspects overseas, including American citizens. She cited an "Alice in Wonderland" predicament in which she was expected to determine what information should be revealed but unable to challenge the government's secrecy claim. Part of her ruling was sealed and made available only to the government's lawyers.

"I find myself stuck in a paradoxical situation in which I cannot solve a problem because of contradictory constraints and rules — a veritable Catch-22," the judge wrote. "I can find no way around the thicket of laws and precedents that effectively allow the executive branch of our government to proclaim as perfectly lawful certain actions that seem on their face incompatible with our Constitution and laws, while keeping the reasons for their conclusion a secret."

The AP could not determine whether the administration was abusing the national security exemption or whether the public was asking for more documents about sensitive subjects. Nearly half the Pentagon's 2,390 denials last year under that clause came from the National Security Agency, which monitors Internet traffic and phone calls worldwide.

"FOIA is an imperfect law, and I don't think that's changed over the last four years since Obama took office," said Alexander Abdo, an ACLU staff attorney for its national security project. "We've seen a meteoric rise in the number of claims to protect secret law, the government's interpretations of laws or its understanding of its own authority. In some ways, the Obama administration is actually even more aggressive on secrecy than the Bush administration."

The Obama administration also more frequently invoked the law's "deliberative process" exception to withhold records describing decision-making behind the scenes. Obama had directed agencies to use it less often, but the number of such cases had surged after his first year in office to more than 71,000. After back-to-back years when figures steadily declined, the government cited that reason 66,353 times last year to keep records or parts of records secret.

Even as the Obama administration continued increasing its efforts answering FOIA requests, people submitted more than 590,000 requests for information in fiscal 2012 — an increase of less than 1 percent over the previous year. Including leftover requests from previous years, the government responded to more requests than ever in 2012 — more than 603,000 — a 5 percent increase for the second consecutive year.

The Homeland Security Department, which includes offices that deal with immigration files, received more than twice as many requests for records — 190,589 new requests last year — as any other agency, and it answered significantly more requests than it did in 2011. Other agencies, including the State Department, National Transportation Safety Board and Nuclear Regulatory Commission performed worse last year. The State Department, for example, answered only 57 percent of its requests, down from 75 percent a year earlier.

U.S. Citizenship and Immigration Services drove a dramatic increase in the number of times DHS censored immigration records under exceptions to police files containing personal information and law enforcement techniques. The agency invoked those exemptions more than 136,000 times in 2012, compared with more than 75,000 a year earlier. Even though USCIS is not a law-enforcement agency, officials used the exceptions specifically reserved for law enforcement.

The AP's analysis also found that the government generally took longer to answer requests. Some agencies, such as the Health and Human Services Department, took less time than the previous year to turn over files. But at the State Department, for example, even urgent requests submitted under a fast-track system covering breaking news or events when a person's life was at stake took an average two years to wait for files.

Journalists and others who need information quickly to report breaking news, for example, fared worse last year. The rate at which the government granted so-called expedited processing, which moves an urgent request to the front of the line for a speedy answer, fell from 24 percent in 2011 to 17 percent last year. The CIA denied every such request last year.

Under increased budget pressure across the government, agencies more often insisted that people pay search and copying fees. It waived costs in 59 percent of requests, generally when the amount was negligible or the release of the information is in the public interest, a decline from 64 percent of cases a year earlier. At the Treasury Department, which faced questions about its role in auto bailouts and stimulus programs during Obama's first term, only one in five requests were processed at no charge. A year earlier, it granted more than 75 percent of fee waivers. The CIA denied every request last year to waive fees.

The 33 agencies that AP examined were: Agency for International Development, CIA, Agriculture Department, Commerce Department, Consumer Product Safety Commission, Defense Department, Education Department, Energy Department, Department of Health and Human Services, Department of Homeland Security, Department of Housing and Urban Development, Interior Department, Justice Department, Labor Department, State Department, Transportation Department, Treasury Department, Department of Veterans Affairs, Environmental Protection Agency, Federal Communications Commission, Federal Deposit Insurance Corporation, Federal Election Commission, Federal Trade Commission, NASA, National Science Foundation, National Transportation Safety Board, Nuclear Regulatory Commission, Office of Management and Budget, Office of the Director of National Intelligence, Securities and Exchange Commission, Small Business Administration, the Social Security Administration and the U.S. Postal Service.

Four agencies that were included in AP's previous analysis of FOIA performance did not publicly release their 2012 reports. They included the Office of National Drug Control Policy, the Office of Science and Technology Policy, the Council on Environmental Quality and the Office of Personnel Management.