The Senate Select Committee on Intelligence said it would hold a closed markup session on Thursday, the first legislative step toward a reauthorization vote long sought by Republicans including President Bush.

The American Civil Liberties Union accused the committee of rushing the process and said lawmakers could use their secret proceedings to enhance the Bush administration's subpoena powers and its authority to conduct searches and surveillance.

Sarah Little, spokeswoman for the Republican chairman of the committee, Sen. Pat Roberts of Kansas, said the meeting was closed "because they will discuss actual intelligence operations and how the Patriot Act applies to those operations."

But ACLU Executive Director Anthony Romero said in a statement: "One reason that people across the political spectrum are concerned about the Patriot Act is that so much of it is shrouded in secrecy."

"Now, lawmakers are trying to keep legislation to reauthorize the Patriot Act secret as well," he added.

The Patriot Act, regarded warily by civil libertarians on both ends of the political spectrum, expanded the government's police powers in the wake of the 2001 attacks.

Lawmakers who approved the legislation also required 16 of its most controversial sections to expire on Dec. 31, 2005, unless renewed by an act of Congress.