A/HRC/12/38 page 13 racial or religious hatred that constitutes incitement to discrimination, hostility or violence. However, they also admitted that defining which acts might trigger article 20, paragraph 2, of the Covenant remains difficult. Indeed, it is difficult to determine what constitutes incitement to violence, hostility or discrimination or where a line can be drawn between criticism - even if deemed offensive - and hate speech. From a legal perspective, the three mandate holders suggested that each set of facts was particular and could only be assessed and adjudicated, whether by a judge or another impartial body, according to its own circumstances and taking into account the specific context. 39. Defining which expressions may fall under the categories of incitement to commit genocide, violence or discrimination may be an easier task than to determine which expressions amount to incitement to hostility. In the case of genocide, statements inciting violence are more evident to assess. The example of Radio Mille Collines in Rwanda with its calls for Hutus to “kill the cockroaches [Tutsis]” was a clear-cut case of advocacy of racial hatred which constitutes incitement to violence. The three mandate holders recalled that there was a duty to act swiftly when confronted with such cases and to heed early warning signs. There is much to be learned from the relevant international criminal tribunals or courts which have addressed these difficult issues in a number of leading cases. 40. The three experts recalled that the notion of incitement to hostility may, however, be more prone to subjective approaches, very much depending on the perspective taken. Indeed, the alleged perpetrator of hate speech, the alleged victim, the average man on the street or a judge may come up with completely different definitions of what constitutes - or not - incitement to hostility. It is necessary to bear in mind that, whoever interprets the concepts of hostility, there always remains a risk of subjectivity. In comparison with racial issues, which tend to be more clear-cut, the degree of subjectivity may be even higher when religious sentiments and sensitivities are invoked. Eventually, only a mature and informed public opinion can fully guarantee racial and religious harmony, and it is important to be able to build on a set of objective legal criteria. 41. In this context, the three mandate holders referred to the expert seminar on articles 19 and 20 of the Covenant, organized by the Office of the United Nations High Commissioner for Human Rights in October 2008 in Geneva. During the expert seminar, the following objective criteria were identified in order to prevent arbitrary application of national legal standards pertaining to incitement to racial or religious hatred: (a) The public intent of inciting discrimination, hostility or violence must be present for hate speech to be penalized; (b) Any limitations on freedom of expression should be clearly and narrowly defined and provided by law. In addition, they must be necessary and proportionate to the objective they propound to achieve, i.e. prohibiting hate speech; (c) Limitations should not threaten the exercise of the right itself. The least intrusive means insofar as freedom of expression is concerned should be used in order to prevent a chilling effect;