Former Imam Abu Hamza has lodged an appeal at the European Court of Human Rights against its ruling that he can
be extradited from Britain to the United States, officials say.
Britain's interior ministry said on Monday that the terror suspect had applied to have the judgement referred to the Strasbourg-based court's Grand Chamber.
In April, the ECHR ruled that London could extradite Abu Hamza and four others to the US, finding that their human rights would not be violated if they were extradited.
The court allowed a three-month stay for appeal, due to expire on Tuesday.
A spokesman for the court confirmed to the AFP news agency that Abu Hamza's lawyers had filed a request and that it was within the deadline.
"The extradition is blocked and a jury must now decide whether the Grand Chamber of the ECHR should take up the case," he added.
Abu Hamza claims he has lost his Egyptian nationality, but Britain considers him an Egyptian citizen. The court listed him as a British national.
'Aiding Taliban and al-Qaeda'
The former imam of the Finsbury Park mosque in north London is wanted in the US on charges including setting up an al-Qaeda-style training camp for fighters in the northwestern US state of Oregon.
He is also accused of having sent money and recruits to assist Afghanistan's Taliban and al-Qaeda and helping a gang of kidnappers in Yemen who abducted a 16-strong party of Western tourists in 1998.
Abu Hamza, who is in his mid-50s and has one eye and a hook for one hand, was jailed in Britain for seven years in 2006 for inciting followers to murder non-believers.
Abu Hamza and the four other terror suspects having their case heard at the ECHR had claimed that the conditions at the ADX supermax prison in Florence, Colorado - used for people convicted of terror offences - and possible multiple life sentences they face would be grossly disproportionate and amount to inhuman or degrading treatment.
But the court held that "conditions at ADX would not amount to ill-treatment".
It found that, given US assurances, 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.
"If the applicants were convicted as charged, the US authorities would be justified in considering them a significant security risk and in imposing strict limitations on their ability to communicate with the outside world," the court said.
"Besides, ADX inmates - although confined to their cells for the vast majority of the time - were provided with services and activities [such as] television, radio, newspapers, books, hobby and craft items, telephone calls, social visits, correspondence with families, group prayer which went beyond what was provided in most prisons in Europe."