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The White House is defending the decision to collect the telephone records of U.S. citizens by labeling it an anti-terrorist measure.

The move by the National Security Agency to gather the phone records of Verizon customers was revealed on Wednesday by U.K. newspaper The Guardian. A court's top-secret order forced Verizon to hand over information about domestic and overseas calls "on an ongoing daily basis."

The court order, which can be seen on The Guardian's Web site, forces Verizon to release all call details or "telephony metadata" created by the carrier for communications between the U.S. and abroad and within just the U.S., including local calls.

The White House hasn't exactly confirmed the report from the Guardian, according to the Associated Press. However, the White House did acknowledge that it has been collecting a large amount of phone records from at least one U.S. carrier, Reuters reported.

The Obama administration called the need to gather this information a "critical tool in protecting the nation from terrorist threats," both Reuters and AP said.

A senior White House official told Reuters that the practice "allows counter terrorism personnel to discover whether known or suspected terrorists have been in contact with other persons who may be engaged in terrorist activities, particularly people located inside the United States."

The official added that the court order applies only to the collection of the phone number and the length of a call and not the names of the parties on the call or the actual conversation.

The order itself identifies the required "telephony metadata" as the source and destination phone numbers, an International Mobile Subscriber Identity Number, an International Mobile station Equipment Identity Number, a trunk identifier, telephone calling card numbers, and the time and duration of the call.

The U.S. Department of Justice may also get involved in the matter, but its attention would be focused on figuring out who leaked the information to The Guardian.

NBC News correspondent Pete Williams said Thursday morning that he was told there would definitely be a leak investigation, according to The Huffington Post. However, a senior White House official told the Post that the suggestion of such an investigation is "premature."