The U.S. Justice Department is probing into the leak of classified information about a controversial secret domestic spying program, the White House said Friday.

White House Spokesman Trent Duffy said the Justice Department is undertaking the investigation on its own, and U.S. President George W. Bush has already been informed about it.

The investigation focuses on disclosures to The New York Times about warrantless domestic eavesdropping conducted by the National Security Agency (NSA) since the Sept. 11 terrorist attacks, an operation authorized by Bush.

The newspaper revealed the existence of the program two weeks ago in a front-page story that acknowledged the news had been withheld from publication for a year, partly at the request of the Bush administration.

"The leaking of classified information is a serious issue. The fact is that al-Qaida's playbook is not printed on Page One and when America's is, it has serious ramifications," Duffy told reporters in Crawford, Texas, where Bush was spending the holidays.

The New York Times declined to comment on the investigation.

Revelation of the secret spying program unleashed a firestorm of criticism of the Bush administration and critics accused Bush of breaking the law by authorizing the program.

The program bypassed a nearly 30-year-old secret court established to oversee highly sensitive investigations involving espionage and terrorism.

U.S. government officials argued that the president has the power to conduct the warrantless surveillance under the Constitution's war powers provision.

Source: Xinhua