WASHINGTON – Since last year's revelations about the National Security Agency's massive communications data dragnets, the spy agency has been inundated with requests from Americans and others wanting to know if it has files on them. All of them are being turned down.

The denials illustrate the bind in which the disclosures have trapped the Obama administration. While it has pledged to provide greater transparency about the NSA's communications collections, the NSA says it cannot respond to individuals' requests without tipping off terrorists and other targets.

As a result, Americans whose e-mail and phone data might have been improperly logged have no way of finding that out by filing open records requests with the agency.

"Were we to provide positive or negative responses to requests such as yours, our adversaries' compilation of the information provided would reasonably be expected to cause exceptionally grave damage to the national security," the NSA wrote to reporters who requested their own records.

"Therefore, your request is denied because the fact of the existence or nonexistence of responsive records is a currently and properly classified matter," it said.

In an apparent reaction to former NSA contractor Edward Snowden's revelations of the NSA's data collections, the number of open records requests filed with the agency more than tripled — from 1,065 to 4,060 — between 2010 and 2013.

The denial rate grew from 33 percent to 82 percent.

The high rejection rate sharply contrasts with Director of National Intelligence James Clapper's pledge to "lean in the direction of transparency, wherever and whenever we can." It also clashes with the NSA's own public assertion that laws enacted in 1974 entitle "individuals to access federal agency records" that are "retrievable by an individual's name."