Dozens of militants linked to ISIS and al-Nusra Front have entered Germany while posing as refugees, Der Spiegel reported, citing sources within the German security services.

Some 60 militants, who have committed numerous massacres of civilians and captives, arrived in Germany, Der Spiegel reported.

They were members of a Syrian militant group called Liwa Owais al-Korani or the Owais al-Korani Brigade.

One fighting on the side of the Free Syrian Army, the Owais al-Korani Brigade switched sides and joined al-Nusra Front – al Qaeda’s affiliate in Syria, the weekly reported.

The group also fought alongside ISIS in the Raqqa province for months.

The group’s militants were involved in “numerous massacres of captured civilians and Syrian soldiers,” the report said, adding that more than 300 people died at the hands of the militants.

German security agencies have been investigating the group’s members in Germany.

Nearly 25 former militants are reportedly being investigated, but another 30 unconfirmed members are believed to be in the country, according to the magazine.

Syria has been the scene of widespread clashes since 2011 when foreign-backed militants launched an attack against the Syrian government.

Ever since, the conflict has claimed the lives of hundreds of thousands of civilians.