WASHINGTON - The chairman of the House Judiciary Committee is threatening to subpoena Attorney General John Ashcroft because the Justice Department has rejected a committee request to reveal how it is using new anti-terrorism powers to monitor Americans.

In a letter sent to the Judiciary Committee Last week, Bush administration officials refused to detail how often they have used the new powers under the USA Patriot Act.

Justice Department spokeswoman Barbara Comstock said Tuesday the information would be sent to the House Intelligence Committee.  Other House members could request it from there, she said.

The Judiciary chairman, Rep. James Sensenbrenner, R-Wis., noting that his committee is responsible for monitoring the Justice Department, said he expects to receive the information by Sept 1.

"I've never signed a subpoena in my 5-1/2 years as chairman," Sensenbrenner said in an interview with the Milwaukee Journal Sentinel.  "I guess there's a first time for everything."

Comstock said the Justice Department has an army of lawyers working to answer many of the questions asked by Sensenbrenner's committee, which are complicated and require research.

The USA Patriot Act, signed by President Bush last year, gave the government broad new powers to monitor people in the United States if they are suspected to have ties with terrorists.  The Patriot Act expands the FBI's power to tap telephone calls, demand records from bookstores and libraries and enter places of worship.

In early June, Sensenbrenner and Rep. John Conyers, the ranking Democrat on the Judiciary Committee, sent Bush officials 50 questions seeking details on how often law enforcement agents have used the new powers.

The Justice Department sent replies to some of the questions in late July but left many of the most important unanswered, according to Jeff Lungren, a Judiciary Committee spokesman.

Very little is known about how often the government relies on the Patriot Act in the terrorism investigations.  In July, several libraries across the nation said FBI agents had demanded information on reading records.