Maassen told Monday's symposium, called to discuss the global threat posed by militant Islamists, that "a worsening security situation needed corresponding adjustments" in the powers and resources given to security authorities. Among other things, he suggested tighter supervision of conduct for convicted Islamists and the introduction of electronic tagging.
He also criticized a recent ruling by Germany's highest court, based on personal privacy concerns, to revoke some anti-terror powers accorded to the authorities under a 2009 law.
Maassen said the decision ignored the new dangers posed by the jihadist group "Islamic State" ("IS"), telling the some 300 security experts gathered at the meeting in the German capital that the extremists were planning to carry out terrorist attacks both on German soil and against German interests abroad.
The authorities received tip-offs about planned terrorist acts on a daily basis, he said, also warning that radical Islamists were "the most dynamically growing extremist scene in Germany."
In light of the growing threats, he called for better cross-border exchange of information within Europe to counter criminal and terrorist groups.
He also spoke about the risk posed by "IS" fighters who entered Germany disguised as refugees, saying this infiltration should be taken more into account in security planning and strategy. Speaking of a "security deficit," he said he was concerned about the large number of migrants without valid passports and whose identity had not been certainly established.
Maassen also called on the intelligence community to review the threat not only from Islamist fundamentalist groups, but also from right-wing organizations that have been carrying out attacks on refugee shelters in Germany on an almost weekly basis.
He warned that the political climate in Germany was "a lot rougher" than it used to be, as former non-voters and disaffected supporters of the established parties become radicalized against the backdrop of the refugee crisis.
German Chancellery Minister Peter Altmaier echoed Maassen's call for a better exchange of data between intelligence agencies, saying that current challenges could be met only by enhanced cooperation between agencies and police authorities within the framework of the rule of law.
He said the government wanted to ensure that in the future, information aimed at preventing terrorism could also be exchanged to avoid possible attacks.
tj/jm (AFP, dpa)Timothy Jones