ASHINGTON, April 25 — Attorney General John Ashcroft has ruled that illegal immigrants who have no known links to terrorist groups can be detained indefinitely to address national security concerns.
Mr. Ashcroft was ruling in the case of a Haitian immigrant who had won the right to be released on bail while awaiting a decision on his asylum claim. Mr. Ashcroft did not argue that the man was a security threat, but said that his release and that of others like him "would tend to encourage further surges of mass migration from Haiti by sea, with attendant strains on national security and homeland security resources."
Because immigration judges are part of the Justice Department, rulings made by Mr. Ashcroft must serve as the basis for any decisions.
The decision will have an immediate effect on Haitian immigrants in Florida. But Mr. Ashcroft said the nation's immigration judges should rule similarly in bail hearings involving other illegal immigrants when the government provides evidence that extended detention is needed to protect the country.
It was unclear how widely the policy would be enforced. But outraged advocates for immigrants said it would impose unnecessary hardships on immigrants and asylum seekers who pose no security risk.
This policy shift is the latest effort by the Bush administration to use the detention of immigrants as a tool to address security concerns and prevent terrorist attacks. In March, officials said they would detain people from Iraq and 32 other countries who arrive at airports and border crossings seeking political asylum.
The government has also detained dozens of immigrants without charge as material witnesses in terrorism cases.
This is the first time, however, that officials have decided to detain immigrants who have no links to terrorism in an effort to address broader security concerns. Until now, judges in bail hearings focused on each individual immigrant and whether he or she would return to court or pose any danger to local communities.
Human rights groups, including Amnesty International and the Lawyers Committee for Human Rights, sharply criticized the policy shift.
"It's shortsighted, it's wrong and it does not make us safer," said Elisa Massimino, who runs the Washington office of the lawyers group. "What it means is that these people will languish in detention without the opportunity to prove to a judge or anyone else that they don't pose a threat to national security."
David Joseph, the detained Haitian immigrant in question in Mr. Ashcroft's ruling, scrambled to shore last Oct. 29 along with more than 200 other Haitians after their boat ran aground off Miami. Mr. Joseph and many others applied for political asylum.
Immigration advocates and lawmakers from both parties immediately called on the president and Gov. Jeb Bush of Florida to order the Haitians' release. Some passengers have been released on bail, but Mr. Ashcroft's decision will ensure that the rest remain in detention until claims for asylum are decided.
Mr. Ashcroft said his ruling was necessary to discourage mass migration from Haiti, which he described as a staging point for Pakistanis and Palestinians hoping to enter the United States illegally, a charge that was disputed by advocates for immigrants.
He said the Coast Guard was wasting precious resources focusing on Haitians trying to enter the United States by boat. With the war against terrorists draining resources, officials lack the capacity to screen Haitian immigrants individually to determine whether they present national security risks, he said.
"Under these circumstances," Mr. Ashcroft wrote in his decision on April 17, "it is reasonable to make a determination that aliens arriving under the circumstances presented by the Oct. 29 influx should be detained rather than released on bond."
Bill Schulz, the executive director of Amnesty International, said he recognized the government's right to protect the public from terrorism. But he said officials also had an obligation to asylum seekers.
"International standards state that the detention of asylum seekers should normally be avoided and is justified only in limited cases prescribed by law," Mr. Schulz said.