Attorney General John Ashcroft said Monday he won't name all those detained in the terrorism investigation because he doesn't want to create a "public blacklist" that would violate their privacy or aid Usama bin Laden.

"The law properly prevents the department from creating a public blacklist of detainees that would violate their rights," Ashcroft told a news conference called to announce his appointment of a special master to oversee compensation to victims of Sept. 11.

More than 1,000 individuals across the country have been detailed by federal and state authorities investigating the terrorist attacks on New York and Washington. Most are being held on immigration violations; others are charged with unrelated criminal offenses or being held as material witnesses.

Civil libertarians have criticized the Justice Department for not providing more information about those detained.

But Ashcroft said no one has been detained who has not violated some federal law, and no detainee has been denied the right to contact a lawyer. "They are not being held in secret," he said.

Providing a complete list of the detainees, Ashcroft said, also might be helpful to bin Laden, whom U.S. authorities have named as the prime suspect behind the Sept. 11 attacks.

"If he wants such a list, he'll have to try and assemble it himself," Ashcroft said.

The Justice Department is preparing an undated accounting of the numbers of those who have been detained for various reasons during the course of the investigation and will release it later this week, Ashcroft said. But names will not be provided.

"We believe that when we have arrested violators of the law that we think have been associated with terrorism, that is a valuable component of defending the United States of America," he said.