The United States on Monday parried a question on whether any Pakistanis are on specific watch list and hunted by US authorities as a part of a larger terrorist crackdown.

"No, I haven't heard that. I have to refer you to the Department of Homeland Security for more on that," White House Press Secretary Dana Perino said while replying to a question at a press conference.

The query was in the context of a media report over the weekend that each day thousands of pieces of intelligence information from around the world -- field reports, captured documents, news from foreign allies and sometimes even idle gossip -- arrive in an office in McLean, Virginia, where analysts feed them into the nation's central list of terrorists and terrorism suspects.

The programme Terrorist Identities Datamart Environment is a storehouse for data about individuals that the intelligence community believes might harm the United States.

TIDE is the wellspring for watch lists distributed to airlines, law enforcement, border posts and US consulates. It was created to close one of the key intelligence gaps revealed after September 11, 2001.

The Washington Post reported that in trying to address one problem the TIDE has brought about others.

Ballooning from about 100,000 files in 2003 to about 435,000 now, the growing database threatens to overwhelm the people who manage it, The Post reported.