In its communication to the Council and the European Parliament of 24 November 2005 on improved effectiveness, enhanced interoperability and synergies among European databases in the area of Justice and Home Affairs, the Commission outlined that authorities responsible for internal security could have access to Eurodac in well-defined cases, when there is a substantiated suspicion that the perpetrator of a terrorist offence or other serious criminal offence has applied for international protection. In that communication, the Commission stated that the proportionality principle requires that Eurodac be queried for such purposes only if there is an overriding public security concern, that is, if the act committed by the criminal or terrorist to be identified is so reprehensible that it justifies querying a database that registers persons with a clean criminal record, and concluded that the threshold for authorities responsible for internal security to query Eurodac must therefore always be significantly higher than the threshold for querying criminal databases.