The agency told the newspaper one reason for the drop could be higher conviction rates and long sentences for those accused of such crimes. The number of migrants entering Germany also dropped significantly in 2017.

However, the far-right extremist scene continued to pose a significant threat, the agency told the newspaper, citing a recent increase in networking and cooperation among such groups across Europe.

Right-wing rock concerts in Germany were now attended by neo-Nazis from Italy, Austria, Switzerland, the Czech Republic, Hungary, and Slovakia, while German right-wing radicals were participating in neo-Nazi marches in Athens, Budapest, and Sofia, it said.

No comment was immediately available from the domestic intelligence agency, or the interior ministry, which oversees that agency.

The Neue Osnabrücker Zeitung newspaper said preliminary government data showed the number of attacks against migrant centers had continued to decline this year.

It said 74 such attacks were registered by the federal criminal police in the first six months of 2018, compared to 174 in the same period of 2017, and more than 700 attacks in the same 2016 period.