Supreme Court justices voiced concern Wednesday about including former Attorney General John Ashcroft and FBI Director Robert Mueller in a lawsuit that claims prisoners detained after the Sept. 11 attacks were abused because of their religion and ethnicity.

Yet the court offered no clear indication that it was prepared to order Ashcroft and Mueller removed from a suit filed by Javaid Iqbal, a Pakistani Muslim who spent nearly six months in solitary confinement in New York in 2002.

Iqbal, since deported from the United States, says Ashcroft, Mueller and others implemented a policy of confining detainees in highly restrictive conditions because of their religious beliefs or race.

"The question here is, who is responsible?" said Alexander Reinert, Iqbal's Yonkers, N.Y.-based lawyer.

Solicitor General Gregory Garre argued on behalf of Ashcroft and Mueller that nothing in Iqbal's complaint ties the allegedly discriminatory acts of lower-level officials to his clients.

The case will help determine when Cabinet officers and other high-ranking officials can be sued over allegations that lower-level government workers have violated people's civil rights.

A federal appeals court said the lawsuit could proceed, but the Bush administration says the high-ranking officials should be dismissed from the suit because Iqbal lacks evidence that they intended or condoned the harsh treatment.