Security experts are warning of copycat attacks, following extensive media coverage of the brutal murder of a British soldier in suburban London.

Drummer Lee Rigby, 25, was hacked to death in a knife attack on Wednesday just yards from the Royal Artillery Barracks in Woolwich.

The two suspects in the killing were shot and wounded by police and are now in hospitals under armed guard.

Two other people - a 29-year-old man and a 29-year-old woman - have been arrested on suspicion of conspiracy to murder.

Rigby, who had a two-year-old son, had last been deployed to Afghanistan in 2009.

Soldiers have long been seen as targets by Islamic extremists.

In Australia, three men were jailed in late 2011 over a terror plot to kill soldiers at the Holsworthy Army Base in Sydney.

"It's not the first time there has been a plot to go specifically after soldiers, but obviously this is the first successful one from an al-Qaeda-inspired point of view," terrorism expert Andrew Silke, from the University of East London, said of Wednesday's attack.

"A lot of the terrorists very much see themselves as soldiers fighting a war."

Last month, three British men were jailed for planning terror attacks at a town which for years was the first to receive soldiers killed in Afghanistan.

Another pair were jailed the same month over an al-Qaeda-inspired plot to send a remote-controlled toy car into an army reservist centre.

And in 2008, another man, Parviz Khan, was jailed for life for plotting to kidnap and kill a British Muslim soldier. He admitted he intended to film his beheading.

Professor Silke says so-called lone wolf attacks using simple methods have become more common as al-Qaeda is weakened.

And he warns there could be more to come.

"We know from research whenever a terrorist attack gets an awful lot of media attention it leads to copycats and we get a lot of other groups being inspired by it saying 'Why don't we do something similar'," the academic told AAP.

The University of Reading's Dr Christina Hellmich agrees "individualised jihad" is likely the kind of attack we will see in the future.

Defence analyst Matthew Henman argues the suspects' failure to flee on Wednesday and their politically-fuelled rants afterwards, suggest "an effort to maximise publicity".

News outlets have named one of the attackers as 28-year-old Michael Adeboloja, a British citizen of Nigerian descent, who was reportedly raised a Christian but became interested in Islam as a teenager.

British Prime Minister David Cameron said the Woolwich attack was "a betrayal of Islam" and the best approach was to "go about our normal lives".

"We will never give in to terror or terrorism in any of its forms," he said on Thursday.

The Australian National Imams Council has urged clerics in Australia to use their Friday sermons to condemn the attack "in no uncertain terms".

Muslims Australia's Keysar Trad on Thursday said "it takes a sick and twisted mind to hack another person with a meat cleaver".

 

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