There are 11,000 blank Syrian passports in the hands of ISIS, raising concerns about the possibility of fake identities for jihadists, German newspaper Bild am Sonntag reported.
German authorities have drawn up a list of serial numbers belonging to blank passports that could be used by the group, Bild am Sonntag reported, per Newsweek.
A spokeswoman for the federal police told Bild am Sonntag that "developments in connection with the refugee situation have shown that terrorist organisations are using the opportunity to (smuggle) potential attackers or supporters into Europe and Germany undetected."
She added that "fake or altered passports are mostly used for illegal entry without further motives like carrying out a terrorist attack."
Newsweek noted that over 8,000 passports checked by German authorities were found to be fake in 2016. However, it could not be established how many of these passports could be traced to ISIS in Syria.
According to RT, the Bild report follows information that a number of Syrian extremists linked to IS terrorist groups have been seeking asylum in Germany.
It is believed that at least 60 members of militant groups Syrian Liwa Owais al-Korani or Owais al-Korani Brigade had entered the country as refugees.
Based on information released by The Federal Office for Migration and Refugees (BAMF), Germany received close on 750,000 asylum applications in 2016, the majority of which came from Syria with 268,866 applications. There were 127,892 applications from Afghanistan and a further 97,162 applications from Iraq.