President Obama was unaware of a program intercepting German Chancellor Angela Merkel's phone calls, along with those of other world leaders, until an internal administration review revealed the existence of the operation and Obama put a stop to it, according to a report in the Wall Street Journal.

The internal review found that the National Security Agency spying was widespread, monitoring some 35 world leaders. Merkel and other European leaders in the last week have voiced their outrage as revelations about the monitoring of Merkel's phone, along with NSA collection of phone call data in France became known.

The revelations surfaced as part of the latest information dump by NSA leaker Edward Snowden. He leaked a memo showing the agency asked U.S. officials to share their contact lists, using the data to launch surveillance on foreign leaders.

The White House did not immediately respond to a request for comment. On Sunday night the NSA released a statement saying the head of the agency never alerted Obama or consulted him on the surveillance involving Merkel.

"Gen. Alexander did not discuss with President Obama in 2010 an alleged foreign intelligence operation involving German Chancellor Merkel, nor has he ever discussed alleged operations involving Chancellor Merkel. News reports claiming otherwise are not true," said NSA spokesman Vanee Vines.

Army Gen. Keith Alexander, the NSA’s director, is expected to step down in April.

The White House has reached out to Merkel over the last week, stressing the importance of the U.S. relationship with Germany. Obama phoned Merkel to discuss the matter and White House spokesman Jay Carney said the U.S. isn't monitoring and won't monitor Merkel, although he did not say whether the NSA had intercepted her phone calls in the past.

House Intelligence Committee Chairman Mike Rogers, R-Mich., on Sunday suggested that the Europeans are probably doing the same type of monitoring of President Obama.

"They don't have necessarily the same type of oversight of their intelligence services that we do and their compartmentalization is much smaller than ours," He said on CNN's "State of the Union."

Rogers pointed out that Obama's BlackBerry is encrypted, which suggested it's a defense against other countries that may be trying to monitor his communications.

"I think they need to have a better oversight structure in Europe," Rogers said. "I think they would be enlightened to find out what their intelligence services may or may not be doing in the interests of their own national security."

The WSJ reported that traditionally the U.S. and four other countries – known as the “Five Eyes” – don't spy on each other. The five eyes are: The U.S., U.K., Canada, Australia and New Zealand.

Secretary of State John Kerry traveled to Europe last week to try to make headway on the Mideast peace process and talk to allies about Syria and Iran. Instead, much of his time was consumed with defending U.S. spying policies as allies expressed outrage and anger over being caught in the surveillance dragnet.

Over the summer, Obama initiated a thorough review of U.S. surveillance practices, which is still ongoing and is likely to take on more significance and stir more Congressional scrutiny once it is finished.

The review is unlikely to conclude before the top two leaders at the National Security Agency depart in the Spring. Alexander and his deputy, John Inglis, are expected to depart in April after a turbulent year for the agency.

Over the summer, Snowden's revelations that the agency engaged in the collection of private citizens' telephone, email and social-media data sparked outrage on Capitol Hill and among world leaders.

The controversy over the NSA spying on Merkel and other world leaders gives more fuel to the agency's biggest critics. Sen. Ron Wyden, D-Ore.,and Sen. Mark Udall, D-Colo., have been warning for more than two years that the NSA has been conducting a massive dragnet on phone and Internet records.

They wrote a bill that would limit the federal government's ability to collect data on Americans without a demonstrated link to terrorism or espionage and reform the way the Foreign Intelligence Surveillance Court operates.

Susan Ferrechio contributed to this report