WASHINGTON — The U.S. government’s aggressive prosecution of leaks and efforts to control information are having a chilling effect on journalists and government whistle-blowers, according to a report released Thursday on U.S. press freedoms under the Obama administration.

The Committee to Protect Journalists conducted its first examination of U.S. press freedoms amid the Obama administration’s unprecedented number of prosecutions of government sources and seizures of journalists’ records. Usually the group focuses on advocating for press freedoms abroad.

Leonard Downie Jr., a former executive editor of The Washington Post, wrote the 30-page analysis entitled “The Obama Administration and the Press.” The report notes President Obama came into office pledging an open, transparent government after criticizing the Bush administration’s secrecy, “but he has fallen short of his promise.”

“In the Obama administration’s Washington, government officials are increasingly afraid to talk to the press,” wrote Downie, now a journalism professor at Arizona State University.

“The administration’s war on leaks and other efforts to control information are the most aggressive I’ve seen since the Nixon administration, when I was one of the editors involved in The Washington Post’s investigation of Watergate,” he wrote.

Downie interviewed numerous reporters and editors, including a top editor at The Associated Press, following revelations this year that the government secretly seized records for telephone lines and switchboards used by more than 100 AP journalists. Downie also interviewed journalists whose sources have been prosecuted on felony charges

Those suspected of discussing classified information are increasingly subject to investigation, lie-detector tests, scrutiny of telephone and email records and now surveillance by co-workers under a new “Insider Threat Program” that has been implemented in every agency.

“There’s no question that sources are looking over their shoulders,” Michael Oreskes, the AP’s senior managing editor, told Downie. “Sources are more jittery and more standoffish, not just in national security reporting. A lot of skittishness is at the more routine level. The Obama administration has been extremely controlling and extremely resistant to journalistic intervention.”

To bypass journalists, the White House developed its own network of websites, social media and even created an online newscast to dispense favorable information and images. In some cases, the White House produces videos of the president’s meetings with major figures that were never listed on his public schedule. Instead, they were kept secret – a departure from past administrations, the report noted.

Frank Sesno, a former CNN Washington bureau chief who is now director of George Washington University’s School of Media and Public Affairs, told Downie the combined efforts of the Obama administration are “squeezing the flow of information.”

In response to the report, White House spokesman Eric Schultz said Obama had committed his administration to work toward unprecedented openness. He said it’s the first administration to release White House visitor records.