Germany's domestic intelligence service says it has created a single list of its sources among extremist groups, fulfilling a key demand from lawmakers investigating the agency's failure to crack down on a far-right terror group.

The National Socialist Underground, or NSU, is suspected of killing 10 people — mostly migrants — between 2000 and 2007. Revelations that several security agencies had sources close to the group but failed to stop it caused national uproar after its existence was uncovered in late 2011.

Domestic intelligence chief Hans-Georg Maassen said in a statement Monday that his agency would gain "a comprehensive insight into the country-wide access to all areas of extremism."

Lawmakers plan to establish a panel of inquiry next week to examine the role intelligence sources played in the NSU case.