The FBI and the Department of Homeland Security are alerting law enforcement to threats of violence aimed at screenings of the Joker film, which opened in theaters Friday.

In a joint intelligence bulletin obtained by several news outlets including ABC News , federal authorities said they have received tips about social media posts calling for unspecific mass shootings.

In a statement to HuffPost, the FBI confirmed that it is looking into the matter.

While our standard practice is to not comment on specific intelligence products, the FBI is in touch with our law enforcement and private sector partners about the online posts, the agency said. As always, we encourage the public to remain vigilant and to promptly report suspicious activity to law enforcement.

DHS declined to provide address the document directly, stating it is against its policy to comment on Law Enforcement Sensitive documents such as Joint Information Bulletins.

According to CNN , the bulletin noted that both agencies and the National Counterterrorism Center remain concerned that the volume of threatening language may lead to lone offender violence. However, there are currently no specific or credible threats.

The memo also warns that so-called clowncels a subset of the incel , or involuntary celibate, community have been referenced in some of the threats.

Incels, the FBI added, have been responsible for at least 27 killings in the U.S. and Canada since 2014.

Oscar-nominated Joaquin Phoenix plays Arthur Fleck, the films infamous central character who eventually becomes Batmans arch nemesis. who engages in murder after being outcasted by society.

Fleck, an outcast and unsuccessful clown-paint-wearing comedian, has been portrayed as bearing psychological similarities to real-world mass shooters, fueling controversy in over the movies potential to influence violence, as it portrays graphic scenes including gun violence and a riot.

At least two movie theater chains AMC and Landmark banned face masks from being worn at showings of the film, the latter companys ban stretching also to face paint and costumes.