Britain can extradite jailed radical Muslim preacher Abu Hamza and five other alleged terrorists to the United States, the European Court of Human Rights ruled Tuesday.

The court found "there would be no violation of Article 3 (prohibition of inhuman and degrading treatment) of the European Convention on Human Rights" if the six were extradited, but allowed a three-month stay for an appeal.

The defendants had complained that conditions at the ADX supermax prison in Florence, Colorado and possible multiple life sentences they face would be grossly disproportionate and amount to inhuman or degrading treatment.

The court said in its ruling that Mustafa Kamal Mustafa, as Abu Hamza is also known, and the five others -- Babar Ahmad, Haroon Rashid Aswat, Syed Tahla Ahsan, Adel Abdul Bary and Khaled Al-Fawwaz -- could be extradited.

It held that "conditions at ADX would not amount to ill-treatment".

Abu Hamza, the former imam of the Finsbury Park mosque in north London, is wanted in the United States on charges including setting up an Al-Qaeda-style training camp for militants in the northwestern US state of Oregon.

He is also accused of having sent money and recruits to assist Afghanistan's hardline Taliban and Al-Qaeda and helping a gang of kidnappers in Yemen who abducted a 16-strong party of Western tourists in 1998.

Hamza, who has one eye and a hook for one hand, was jailed in Britain for seven years in 2007 for inciting followers to murder non-believers.

The European Court of Human Rights had previously halted the extradition of Egyptian-born Hamza and three of the other men to the United States on terror charges, saying the case needed further examination.

The court later found that, given US assurances, that there was no real risk the men would either be designated as enemy combatants and be subject to the death penalty or subjected to extraordinary rendition.

The four applicants, joined by the other two, had also launched a complaint concerning conditions of detention at ADX Florence and the length of their possible sentences, if extradited and convicted in the US.