The terror rampage in Paris was an escalation of recent lone wolf attacks in Sydney, New York and Ottawa, according to the chairman of the US house committee on homeland security.
Mike McCaul said the level of sophistication of the raid by at least three gunmen at the Paris office of the satirical newspaper Charlie Hebdo on Wednesday pointed to foreign fighters returning to the West to perform attacks.
The gunmen, armed with automatic weapons, killed 12 people.
"This is a very different style of attack to what we have seen with the 'Hate Sheikh' in Sydney, the New York incident with the axe for instance that was inspired over the internet and the Canadian attack in Ottawa," McCaul told CNN.
"This is well co-ordinated, very sophisticated, very professional, which leads me to believe they received training."
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Last month in Sydney two hostages died when self-proclaimed sheikh Man Haron Monis took over the Lindt cafe in Sydney's Martin Place.
In October Zale Thompson attacked four New York police officers with an axe, injuring two, and in the Canadian capital of Ottawa Michael Zehaf-Bibeau shot dead a corporal guarding the tomb of the unknown soldier at the National War Memorial and then entered the nearby parliament building and fired shots.
"The dual threat is the home grown violent extremists but also the foreign fighter who can travel overseas, be trained and then come back," McCaul said.
"The level of sophistication (in the Paris attack) concerns me greatly because this is really one of the first of what I consider to be foreign fighters now returning and pulling off a major act of terrorism."
