As the Royal Wedding nears and the eyes of the world turn to London this week, a radical Muslim cleric in Britain who plans to protest outside the ceremony tells ABC News the celebrations are a "prime target" for Al Qaeda franchises and wannabe jihadis alike.
Top Al Qaeda operatives Ayman al-Zawahiri and Anwar al-Awlaki are "actively encouraging people to carry out [do-it-yourself] operations]" similar to the attempted attack by alleged 'Underwear Bomber' Umar Farouk Abdulmutallab on a Christmas Day flight from Amsterdam to Detroit in 2009, says Anjem Choudary in an interview on the current episode of "Brian Ross Investigates."
"There's nothing really which is outside of the realm of a possible attack, from biological to nuclear to very high profile events like 9/11," said Choudary, whose extremist Islam4UK organization was recently banned by the British government under counter-terrorism laws. "So I think it's a case of all-out war."
He said there is a "very real possibility" that attackers "will come into [Britain] via the sea or via ports where they can slip under the security."
While the Royal Wedding "is certainly a target for those people who want to cause havoc in Britain," Choudary said as a Muslim residing in Britain he lives "under a covenant of security" and as such is "not allowed to carry out such an operation." However, he said "there is a difference of opinion" and while he stopped short of supporting a violent attack by those living outside Britain, he did say, "I do believe that a Muslim, whenever he is being attacked, or whenever his land is being occupied, or whenever his honor is being violated, he has a divine duty to defend himself."
Choudary does support, and intends to be part of, a planned protest by the activist group "Muslims Against Crusades" outside Westminster Abbey, where the wedding is being held, during the wedding on April 29.
Scotland Yard rejected the group's application to demonstrate, but the group says it is going ahead with its protest, with a spokesman telling ABC News, "We plan to make the Royal Wedding a day that the world will never forget and although we are non-violent, we are confident that our presence will be enough to make a nightmare out of the situation, God willing."
Scotland Yard would not comment on whether it considers Muslims Against Crusades a direct threat to the royal couple and spectators' safety, but security officials previously told ABC News they are more concerned the group's vague threats could spur violence by other, "self-radicalized" Muslims.
For weeks Muslims Against Crusades has posted on its website a continuous countdown clock to the wedding under the title "Muslims to Disrupt Royal Wedding."
"Brian Ross Investigates" premiered in April 2010 as a weekly digital investigative news show and airs every Friday on Hulu.com and ABC News Now, the network's 24-hour news channel available throughout the U.S. and Europe. Each show is also available on mobile devices.
The current episode looks at potential security threats in London, including resurgent Irish terror groups who experts say want an attack inside England.