About a dozen migrants may have entered Germany on forged Syrian passports like those used by two Paris suicide bombers, according to a news report Tuesday which authorities did not confirm.
Bild newspaper, citing unnamed government sources, said the passports bore the "same forgery characteristics" as those carried by two men involved in the November 13 France attacks claimed by ISIS.
The passports were stolen blanks issued by the Syrian government, but filled in by forgers with the personal details of people who then joined tens of thousands on the refugee trail to Europe, according to Bild.
The report said German authorities did not know where the "about one dozen" arrivals were now, having entered the country before November 13, and that no fingerprints had been taken of them.
Germany's Office for Migration and Refugees now only had copies of the passports, which Bild said had been issued in 2013 in Raqqa, now ISIS's de facto Syrian capital.
The German interior ministry, contacted by AFP, declined to comment on the claims "for tactical reasons", but stressed that it was aware of the risk criminals and extremists could use forged Syrian passports.
German newspaper Welt am Sonntag, citing Western intelligence sources, reported on Sunday that ISIS may have stolen "tens of thousands" of blank passports in Syria, Iraq and Libya that it could use to smuggle its fighters into Europe.
The two unidentified Stade de France attackers in Paris appear to have used fake Syrian passports to enter Europe along the migrant trail.
Germany is Europe's top destination for refugees, most of whom travel through Turkey and the Balkans, and expects more than one million arrivals this year.
Europe's biggest economic power has to date maintained an open-door policy for Syrians escaping their country's bloodshed, giving them "primary protection" -- the highest status for refugees.
A deputy leader of Angela Merkel's Christian Democrats, Julia Kloeckner, demanded Tuesday that Germany tighten its controls and immediately re-introduce personal interviews of all asylum seekers arriving in Germany.SHOW MORE