WASHINGTON, Aug. 23 — The Bush administration has confirmed for the first time that American telecommunications companies played a crucial role in the National Security Agency’s domestic eavesdropping program after asserting for more than a year that any role played by them was a “state secret.”

The acknowledgment was in an unusual interview that Mike McConnell, the director of national intelligence, gave last week to The El Paso Times in which he disclosed details on classified intelligence issues that the administration has long insisted would harm national security if discussed publicly.

Mr. McConnell made the remarks apparently in an effort to bolster support for the broadened wiretapping authority that Congress approved this month, even as Democrats are threatening to rework the legislation because they say it gives the executive branch too much power. It is vital, he said, for Congress to give retroactive legal immunity to the companies that assisted in the program to help prevent them from facing bankruptcy because of lawsuits over it.

“Under the president’s program, the terrorist surveillance program, the private sector had assisted us, because if you’re going to get access, you’ve got to have a partner,” Mr. McConnell said in the interview, a transcript of which was posted by The El Paso Times on Wednesday.