Ahmad made efforts to secure GPS devices, Kevlar helmets, night vision goggles, ballistic vests and camouflage uniforms, prosecutors said.
U.S. Attorney Preet Bharara called the extraditions "a watershed moment in our nation's efforts to eradicate terrorism."
He added: "As is charged, these are men who were at the nerve centers of Al Qaeda's acts of terror, and they caused blood to be shed, lives to be lost, and families to be shattered."
Al-Masri is not the first ailing Egyptian-born preacher to be brought to Manhattan for trial. A blind sheik, Omar Abdel-Rahman, is serving a life sentence after he was convicted in 1995 in a plot to assassinate then-Egyptian President Hosni Mubarak and in another to blow up New York landmarks, including the United Nations and two tunnels and a bridge linking New Jersey to Manhattan. Abdel-Rahman has numerous health issues, including heart trouble.
The overnight trip to the United States came after a multiyear extradition fight that ended Friday, when Britain's High Court ruled that the men had no more grounds for appeal and could be sent to the U.S. immediately. The men have been battling extradition for between eight and 14 years.
"I'm absolutely delighted that Abu Hamza is now out of this country," British Prime Minister David Cameron said. "Like the rest of the public I'm sick to the back teeth of people who come here, threaten our country, who stay at vast expense to the taxpayer and we can't get rid of them."
"I'm delighted on this occasion we've managed to send this person off to a country where he will face justice," he added.
Al-Masri has been in a British jail since 2004 on separate charges of inciting racial hatred and encouraging followers to kill non-Muslims.
While al-Masri has been portrayed in the British media as one of the most dangerous men in the country, the case against Ahmad in Connecticut has raised concerns among legal experts and human rights advocates.
Some lawyers and lawmakers have expressed concerns because Britain agreed to extradite the London computer expert even though his alleged crimes were committed in Britain and British courts declined to prosecute him for lack of evidence. Ahmad and Ahsan are accused of running websites to support Afghanistan's ousted Taliban regime, Chechen rebels and associated terrorist groups.
Christoffersen reported from New Haven, Conn. Associated Press writers Jill Lawless and Sylvia Hui in London contributed to this report.
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