German authorities are preparing for possible terror attacks on German soil as pressure builds on the militant "Islamic State" (IS) group in Iraq, Hans-Georg Maassen (pictured above) said in an interview on Sunday.

The operation to retake Mosul from the militants could encourage IS supporters in Europe to carry out attacks, Maassen, who heads Germany's domestic intelligence agency, told German public radio Deutschlandfunk.

"That is what we want to prevent and we are preparing ourselves accordingly," the intelligence chief said.

Currently, only a few IS fighters from Germany or Europe have returned home due to IS military defeats, Maassen said.

The number of people leaving Germany or other European countries to fight alongside IS has also leveled off since the Mosul operation began. The number of Germans who traveled to Syria and Iraq had risen sharply from the summer of 2014 to August of this year, but the numbers have now been stagnating, Maassen said.

"My impression is that the fighting in Syria and Iraq is currently not so attractive for German jihadis," he explained, adding that it could be "too dangerous to get there."

On October 17, Iraqi government forces, Kurdish troops and US-backed Sunni fighters started a campaign to liberate Mosul from the militant group. A parallel operation is being carried out by an international anti-IS coalition to retake Syria's Raqqa from the militants.

The US army believes many of the foreign fighters among the estimated 4,500 militants in Mosul will likely end up forming the core of the holdout jihadi force.

Far-right violence

Right-wing extremism is also an area of growing concern in Germany, Maassen told Deutschlandfunk.

"We are concerned that there could be right-wing terrorist individuals or individual cells in Germany," he said. Specifically, Maassen named the "Old School Society" as a possible threat. The group, which has a nationwide network, reportedly planned to carry out attacks on refugees and Salafists, according to Maassen.

A far-right member of the "Reichsbürger" movement wounded four police officers during a shootout on October 19 in the southern German state of Bavaria. One of the officers later died of his injuries.

Germany's recent "Good Living" report noted that hate crimes in Germany soared by 77 percent compared to data from 2015. Anti-foreigner crimes also rose by 116 percent in the last year.

rs/rc     (dpa, Reuters)