Developing: The Associated Press said the U.S. government secretly mined two months’ worth of phone records in what the wire service called a “serious interference” of its constitutional rights to gather and report news.

AP reports the Department of Justice’s collection included records for more than 20 telephones assigned to AP journalists in April and May, spanning across offices in New York, Washington and Hartford, Conn. The Justice Department also accessed a shared fax line and a switchboard. In total, AP estimates at least 100 journalists may have utilized the lines. 

AP President and chief executive Gary Pruitt demanded in a letter to Attorney General Eric Holder that the Justice Department return the records to AP, and destroy the copies.

“There can be no possible justification for such an overbroad collection of the telephone communications of The Associated Press and its reporters,” he wrote. “We regard this action by the Department of Justice as a serious interference with AP’s constitutional rights to gather and report the news.”

AP said it was notified of the collections in a letter Friday from Ronald Machen, a U.S. attorney in Washington. The letter said the Justice Department received a subpoena, although, AP said it remained unclear as to whether a judge or a grand jury signed off.

The U.S. Attorney's Office issued a statement on the matter to FOX Business, saying, "we take seriously our obligations to follow all applicable laws, federal regulations, and Department of Justice policies when issuing subpoenas for phone records of media organizations." It also added that "because we value the freedom of the press, we are always careful and deliberative in seeking to strike the right balance between the public interest in the free flow of information and the public interest in the fair and effective administration of our criminal laws."

It wasn’t immediately clear what the government was seeking in its investigation, however, AP speculated that it could have to do with a story published on May 7, 2012, in which the wire service disclosed details about a Central Intelligence Agency Operation in Yemen to halt an airline bomb plot.

The reporters and editors on the story had their records probed in the Justice Department’s operation, according to AP.

There have been several instances when the government has utilized subpoenas and other methods to push news organizations to reveal confidential sources in the past, although, AP said this particular investigation represents an “unprecedented intrusion.”  

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