Alexandria, Va. ? The Bush administration said Thursday it will seek to execute Zacarias Moussaoui in connection with the Sept. 11 attacks and appealed to European allies to keep cooperating with terrorism investigations despite their opposition to the death penalty.

Moussaoui, 33, should be put to death because he helped plan “the largest loss of life resulting from a criminal act in the history of the United States,” prosecutors said in notifying a federal judge of their intentions.

“Zacarias Moussaoui has demonstrated a lack of remorse for his criminal conduct,” prosecutors wrote in setting up a novel effort to impose the death penalty against a defendant charged with conspiracy, not murder.

The decision by Atty. Gen. John Ashcroft, a longtime death penalty supporter, touched off immediate criticism from anti-terrorism allies who oppose capital punishment.

Officials in Moussaoui’s homeland of France said they would continue general cooperation with the United States but would not turn over any documents that could be used to support his execution.

“I regret this,” French Justice Minister Marylise Lebranchu said of Ashcroft’s decision.

In Britain, where execution also is outlawed, a government spokesman said, “Our position on the death penalty is well known.”

Influencing the jury pool?

Traveling in Miami, Ashcroft announced his decision in a televised news conference and immediately sought to smooth relations with the allies.

“We ask our counterparts in the international community to respect our sovereignty, and we respect theirs, and to the extent that they can cooperate and help us, we welcome that cooperation,” he said.

Moussaoui’s public defender, Frank Dunham Jr., sharply criticized Ashcroft’s news conference as “disgraceful conduct” that could prevent selection of an impartial jury in the Washington area where the trial is slated this fall.

“I am mystified as to why he feels he has to hold a televised press conference other than to influence the jury pool,” Dunham said. “I’ll stop short of calling it unethical, but it’s close to it.”

Moussaoui’s mother in France accused U.S. officials of seeking revenge. “My son is a scapegoat. They can’t find the people who are truly responsible for this crime,” Aicha Moussaoui said.

‘Aggravating factors’

Though Moussaoui never boarded any of the hijacked airliners and was already in custody a month before the attacks occurred, prosecutors said there were several “aggravating factors” why his conduct warranted a death sentence.

Moussaoui participated in the planning “knowing that the act created a grave risk of death to a person,” U.S. Atty. Paul McNulty said in his court filing.

The filing cited the loss of some 3,000 lives on Sept. 11, the maiming of survivors, the disruption of the economy and the killings of hundreds of New York police officers and firefighters at the World Trade Center.

The government will seek to prove that Moussaoui committed the offenses “in an especially heinous, cruel and depraved manner in that they involved torture and serious physical abuse to the victims,” McNulty added.

Prosecutors said Moussaoui mirrored many of the activities of the hijackers. He attended U.S. flight schools and “enjoyed the educational opportunities available in a free society, for the purpose of gaining specialized knowledge in flying an aircraft in order to kill as many American citizens as possible,” McNulty argued.

Victims’ families were split.

Gregory Hoffman, who lost his twin brother at the World Trade Center, said, “Your initial gut reaction is kill him, but at the end of the day, what does that mean? I don’t think taking a life is the answer. And if they want to be killed and martyred, don’t give it to them.”

Terry Corio, 55, who lost her sister in the trade center, said she normally opposes capital punishment, but “in a case as horrible as this … I want the death penalty.”

Legal experts said the prosecution will face challenges in securing a death sentence against a defendant charged not with murder but conspiracy.

“There are no cases like this one,” said Donald Ayer, a former Justice Department prosecutor.