Migrants carrying forged passports from the same workshop as those held by two of the Paris terrorists have entered Europe through Germany, a minister said on Tuesday.
German security authorities believed that several people had entered Germany during November and October travelling on Syrian passports with serial numbers similar to those in the possession of the terrorist group Islamic State, said Joachim Herrmann, the Interior Minister for the southern state of Bavaria.
Two of the bombers from last month's deadly Paris attacks were carrying passports with the same serial numbers, he said.
Concerns that people may have been sent to Germany by the Islamic State was the obvious conclusion, he said.
"Unfortunately, no one knows where the refugees in question are now," Hermann said.
He was confirming a report published earlier on Tuesday in the mass-circulation Bild daily.
Citing security officials, Bild said the travel documents included legitimate passports stolen in al-Raqqa, Syria, Islamic State's self-proclaimed capital. They have been converted for use by persons other than the original holders.
Bild also reported that the passports showed the same forging characteristics as those held by two of the attackers in Paris on November 13. The two were checked as they entered the European Union through the Greek island of Lesbos.
It said the passports of the migrants to Germany had been copied by the authorities as their holders entered the country. No fingerprints had been taken of the holders, who might or might not be genuine refugees.
Another German press report said on Sunday that Islamic State had managed to seize a large number of genuine passports in Syria, Iraq and Libya. The Sunday edition of Die Welt put the number at tens of thousands.
The German authorities confirmed a report in March that around 3,800 blank Syrian passports had been seized by Islamic State in al-Raqqa.