OSLO, Nov. 5 (Xinhua) -- Terror experts said it is worrying that French extremists claimed to be inspired by Norway's Anders Behring Breivik who killed 77 people in 2011, newspaper Aftenposten reported Sunday.
In three different cases, the Norwegian far-right extremist's French supporters have attacked or threatened Muslim population, the report said.
"This is startling and worrying," terror researcher Thomas Hegghammer at the Norwegian Defense Research Institute (FFI) told Aftenposten.
"There have been relatively few Breivik-inspired events in Western Europe since 2011, so such accumulation of cases will be unusual," says Hegghammer, adding that the trend shows current mobilization on the outermost French right side.
"It also shows that we must not underestimate Breivik's influence. He can make comeback as inspirational source under certain circumstances," he said.
The last known example of groups inspired by the Norwegian terrorist is a group called the Defense Command of the French People and the Motherland (CDPPF). They have already attacked and injured five people at the University of Dijon, attacking women with veil and others of minority background.
Jacob Aasland Ravndal, researcher at the Center for Extremism Research at the University of Oslo, said it is something new in Western Europe "that organized groups with a public profile support Breivik's methods and political views."
Breivik set off a car bomb that killed eight people outside government headquarters in Oslo on July 22, 2011 and then killed 69 others in a shooting rampage on Utoya Island, where young members of the governing Labor Party had gathered for their annual summer camp.
In 2012, he was sentenced to 21 years in prison at the Oslo District Court.
Norway's penal code does not have the death penalty or life imprisonment, and the maximum prison term for Breivik's charges is 21 years. However, inmates who are considered a threat to society can be held indefinitely.