Speaking on the Maybrit Illner TV talk show, de Maizière said that the trend in Germany – of ever more people travelling to the Levant to fight for the radical Islamist fighters there – was similar to those in France and Belgium.
Only in Britain has the number fallen back, he said.
The security services know “a great deal about” the Islamist scene in Germany and the 650 Germans in Syria have been “very clearly identified,” said the Christian Democratic Union (CDU) politician.
There are also more than 1,000 high risk individuals who “we know pretty exactly”, he said.
The number of people travelling to the Middle Eastern war zones has been rising for several months.
In mid-January, de Maizière told the Bundestag (German parliament) that 600 people had travelled to the war-torn region.
The Interior Minister was responding to comments made on Thursday George Hans Maaßen, the head of Germany's internal security service, the Bundesamt für Verfassungsschut.
Maaßen said he wished he knew more about the Islamist scene in Germany, complaining of his dependence on other countries' intelligence services – including Britain's GCHQ – and the internet.
“It is amazing how much some people give away about themselves on the internet – as much as pictures of kidnappings in Syria that they participated in as witnesses,” Maaßen told the Südwestpresse on Wednesday.
“The number of of people travelling out there has gone up, and likewise the number of those coming back has,” he said.
“And with that the number of people who have battle experience and know how to handle weapons has also risen.”