BERLIN (Reuters) - The recent mass killing in Norway could easily serve as a blueprint for other anti-Muslim militants, one of Germany's top security officials warned in a magazine interview Sunday.

Anders Behring Breivik killed 77 people in bombing and gun attacks in Norway on July 22, and left detailed instructions on the internet of how he planned the bloodshed without attracting much police attention.

"This could serve as a blueprint for copycats," Alexander Eisvogel, vice-president of Germany's domestic anti-terrorist agency, the Federal Agency for the Protection of the Constitution (BfV), told the news magazine Der Spiegel.

"From the point of view of a terrorist, he has meticulously and carefully considered how to avoid coming into the view of the security services. This ... is an extreme concern for us right now," Eisvogel said.

Separately, the leader of Germany's main opposition party, Social Democrat Sigmar Gabriel, urged German security services and internet service providers to take tougher action against online right-wing extremism.

"If someone on the street in Germany ... said he wanted to persecute other people or even commit attacks, then the public would report him to the police," Gabriel told Deutschlandfunk radio.

"On the internet it's amazingly different. There, insults and even calls to murder are treated as a type of eccentric by-product of freedom."

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