A growing number of migrants arriving in Europe are Islamic State (ISIS) militants plotting terrorist attacks, a senior German police official warned today.
Authorities are aware of 7,900 Islamic radicals in Germany advocating violence and attempting to recruit refugees, according to Mr Maasen.
He said his office receive one or two “fairly concrete tips” a week of planned terrorist activity, calling ISIS extremists “combat-hardened professionals” who are more dangerous than those from al-Qaida.
Newly released figures show more than 950,000 asylum seekers have entered Germany this year so far – with the number of arrivals now expected to outnumber new births in Germany this year.
The figures came as Germany’s European Union (EU) commissioner blamed his country’s “open door” policy for exacerbating Europe’s refugee crisis.
He said: “An amendment to the constitution would be necessary to change the asylum law.
“As long as this is not addressed, there is really only one alternative: billions of aid for the refugee camps in Turkey and other countries.”
Mr de Maiziere demanded Europe to “commit itself to a final generous intake of refugees, one that is appropriate to the suffering of refugees”.
Stricter security at borders has been introduced across Europe in the wake of the Paris attacks that killed 130 people after it emerged at least two of the terrorists posed as refugees to get into Europe.
A fake Syrian passport was found near the body of a suicide bomber who detonated his suicide vest near the Stade de France on November 13.
The revelation has intensified fears that ISIS extremists are passing themselves off as asylum seekers to get into the EU.
Fraudulent Syrian passports are regularly used on the migratory route from Turkey through Europe, with German officials estimating nearly a third of asylum seekers have falsely claimed they were Syria this year.
Syrian passports have become particularly valuable as Balkan countries said they would only open their borders to people fleeing war-torn countries such as Syria, Iraq and Afghanistan.
Clashes between police and refugees stranded at the Greek-Macedonian border have continued to escalate, with hundreds of migrants trying to force their way past police and army into Macedonia.
Frustrated migrants threw rocks and bottles at Macedonian police, pulling apart razor wire marking the border between Greece and Macedonia.