A letter to Attorney General Eric Holder from the Associated Press has revealed that the Justice Department used a secret subpoena to obtain two months of phone records from the news service.
AP President Gary Pruitt called the subpoenas a "massive and unprecedented intrusion," according to CNN.
"These records potentially reveal communications with confidential sources across all of the newsgathering activities undertaken by the AP during a two-month period, provide a road map to AP's newsgathering operations and disclose information about AP's activities and operations that the government has no conceivable right to know," Pruitt wrote in the letter.
The Justice Department has not announced why they are conducting the search, but it is thought to be part of an investigation to find a leak who had revealed information about a thwarted bombing. The AP broke a story last spring that detailed how the CIA was able to stop an al-Qaeda plot to place a bomb on an U.S. bound plane from Yemen, according to NBC News.
Bill Miller, a spokesman for the Justice Department, told NBC News that the subpoenas were obtained by the book and were completely legal.
"Consistent with Department of Justice regulations, the department provided notification to the Associated Press of the receipt of toll records in a letter dated May 10, 2013," Miller said in an email. He went on to say that regulations "do not require notification to the media prior to the issuance of legal process to obtain toll records."
The revelation of the probe brings up issues relating to the First Amendment and the rights of the press to protect their sources.
"We regard this action by the Department of Justice as a serious interference with AP's constitutional rights to gather and report the news," Pruitt said.
Members of Congress agreed the probe may have gone too far.
"The First Amendment is first for a reason," Michael Steel, spokesman for House Speaker John Boehner, said. "If the Obama Administration is going after reporters' phone records, they better have a damned good explanation."
"I am very troubled by these allegations and want to hear the government's explanation," Sen. Patrick Leahy, D-Vt., said. "The burden is always on the government when they go after private information - especially information regarding the press or its confidential sources. I want to know more about this case, but on the face of it, I am concerned that the government may not have met that burden."
CNN legal analyst Jeffery Toobin told CNN that the Obama administration has been especially aggressive in going after leaks. There is no actual federal law protecting the press' sources but past administrations have never gone as far as to force their revelation, according to CNN.
"I have never heard of a subpoena this broad," Toobin said. "It's legal, as far as I can tell. The administration isn't violating the First Amendment. But they are certainly doing more than has ever been done before in pursuing the private information of journalists."
White House spokesman Jay Carney said that the White House was unaware of the subpoenas because subpoenas are handled independently by the Justice Department, according to CNN.
