U.S. and German officials Tuesday said they had traced three of the Sept. 11 hijackers to a terrorist cell operating out of Hamburg, Germany, since at least 1999 and issued arrest warrants for three other members of the cell who are still at large.

German authorities previously issued international arrest warrants for Said Bahaji, Ramsi Binalshibh and Zakariya Essabar. Attorney General John Ashcroft said the three had extensive connections to Mohamed Atta and Marwan Al-Shehhi, the suspected pilots of the hijacked planes that crashed into the World Trade Center in New York, and Ziad Jarrah, suspected of flying the plane that crashed in Pennsylvania.

German Interior Minister Otto Schily, who met with Ashcroft Tuesday, declined to provide information about evidence developed in Germany that the three fugitives planned the attacks, citing the investigation. Ashcroft said others probably also helped in the plot.

Asked why there have been no charges brought in the United States when German authorities have pinpointed three fugitives responsible for planning the attacks, Justice Department spokeswoman Mindy Tucker said, "When we feel it's appropriate to bring charges against individuals, we will do so."

Ashcroft said 12 FBI agents have been assigned to Germany to assist in the investigation.

German authorities arrested a Turkish man trying to board a flight to Iran after authorities found a holy war CD-ROM, a protective suit against biological and chemical weapons and equipment to make a detonator in his bag. The man's lawyer said the bag and the equipment did not belong to his client.

Copies of Anthrax-Contaminated Letters Released

The Justice Department released copies of three letters contaminated with anthrax as it sought help from the public in identifying those responsible for the mail attacks that have killed three people and poisoned more than a dozen others.

The three letters all were dated the same day as the Sept. 11 attacks on New York and Washington and contained anti-American and anti-Israel messages, officials said.

The identical dates are yet another indication that the anthrax attacks were coordinated. Authorities have already said the strain of anthrax in the New York and Washington letters and bacteria found at a Florida publishing company were similar. And the three letters were all postmarked from Trenton, N.J.

Letters sent to NBC's Tom Brokaw and the New York Post appeared identical. Both warned recipients to "Take penacilin now," an apparent misspelling, and also said, "Death to America," "Death to Israel" and "Allah is Great."

The envelope that contained the New York Post letter was written in the same sort of block letters, slanted to the right, as two envelopes addressed to Brokaw and Senate Majority Leader Tom Daschle, released earlier.

The letter to Daschle contained seven lines written in block letters similar to the other two. "You can not stop us. We have this anthrax. You die now. Are you afraid? Death to America. Death to Israel. Allah is great."

Atop all three notes was the date "09-11-01" in identical handwriting. The letters to Brokaw and the New York Post were postmarked Sept. 18. The Daschle letter was postmarked Oct. 9.

Ashcroft said investigators hope to garner new leads by releasing photographs of the letters and to warn Americans of mail to be wary of.

"All of these ... we hope will alert citizens and others to the kind of thing to look for," said Ashcroft.

Despite the dates on the letters, Ashcroft said authorities can't prove a link to the men who carried out the airliner attacks last month.

The FBI is investigating whether additional anthrax-laced letters have been sent. The White House on Tuesday said anthrax was discovered in an offsite mail facility. The origin of the anthrax was unknown. Mail handled at the offsite facility is processed through a postal facility on Capitol Hill that processed the Daschle letter.

Experts in profiling criminals viewed the release of the letters and the identical dates as indications that investigators believe they are dealing with a domestic terrorist capitalizing on the Sept. 11 attacks.

They noted that authorities caught Theodore Kaczynski, the so-called Unabomber, after releasing his 35,000-word "manifesto," which was recognized by Kaczynski's brother.

"The key is access to the bacteria," said Robert K. Ressler, a former FBI criminal profiler.

Investigators have questioned researchers at labs and universities that may have access to anthrax.

The attacks could also be the work of foreign terrorists operating on U.S. soil or a domestic player assisted by foreign elements, said Ressler.

In other developments:

• A federal grand jury in Virginia indicted Mohamed Abdi, a naturalized U.S. citizen from Somalia, on 12 counts of forging his landlord's name on housing subsidy checks. Abdi's name and phone number were found in a car registered to Nawaf Alhazmi, one of the 19 suspected hijackers.

• More than 900 people have been detained in connection with the Sept. 11 attacks, but so far no one has been charged directly with plotting or participating.