A sustained cyberattack was detected on the computer network used by officials of the Executive Office of the President, a White House official said Tuesday.

A White House official told Reuters that, since the cyberattack was detected, measures have been taken to address the activity on the Executive Office of the President's unclassified computer network. Officials have not disclosed who might be responsible for the attack.

"In the course of assessing recent threats we identified activity of concern on the unclassified EOP network. Any such activity is something that we take very seriously. In this case we took immediate measures to evaluate and mitigate the activity," the official told Reuters.

The White House -- of the Executive Office of the President (EOP) -- regularly gets hit with cyberattacks, but the one revealed Tuesday had a more significant duration affecting the function of the system for nearly two weeks.

"Certainly a variety of actors find our networks attractive targets and seek to access to sensitive government information. We are still assessing the activity of concern, and we are not in a position to provide any additional details at this time," the White House official said in a statement.

White House press pool reports sent by email Tuesday night were "significantly delayed," pool reporter Steven T. Dennis of CQ Roll Call told Huffington Post. "Some people are getting pool reports significantly before other people."

The official said the technical measures to address the activity had led to limited access to some EOP network services, and that some of the issues have been resolved, but the work continues. It was not revealed when the activity took place.

A White House internal email, published by the Huffington Post, said "Our computers and systems have not been damaged, though some elements of the unclassified network have been affected. The temporary outrages and loss of connectivity that users have been experiencing is solely the result of measures we have taken to defend out networks."

Only earlier this month, President Barack Obama during a fundraising tour in New York City said cyber terrorism is one of the biggest threats to national security for government and business computer systems.

He said the White House is bracing for a possible doomsday scenario if hackers can successfully penetrate government systems, or break security walls at major banks, reported FOX Business Network.

An attendee at one of the fundraisers told FOX, "The president is worried that cyber criminals could literally wipe out the identities of millions of people through some breach of government systems and that could lead to massive chaos."

President Obama said he expects cyber terrorism to only grow in the years ahead.

"He said 15 years ago, cyber terrorism wasn't even on the radar screen, but that it will be one the biggest concerns for whoever is president after him," the attendee said.