Atrocity Prevention Act This bill establishes annual reporting requirements for the Department of State regarding countries and regions at risk of atrocities (such as genocide). The bill also makes permanent a requirement, currently set to expire in 2025, for the State Department to report annually to Congress on U.S. efforts to prevent and respond to atrocities. Under this bill, the State Department must annually (1) rank countries and regions at risk of atrocities as high, medium, or low risk, and (2) assess the risks related to providing security assistance and cooperation to medium- and high-risk countries. For each country identified as high- or medium-risk, the State Department must determine whether the United States should continue to provide security assistance and cooperation. For each country newly identified as high- or medium-risk, the State Department must address whether U.S. security assistance and cooperation may be used to perpetrate atrocities or exacerbate risk factors for the commission of atrocities. For each country that was already identified as high- or medium-risk in the previous report, the State Department must assess any relevant changes in the country since the last report. Finally, the bill requires that the report be submitted in unclassified form. The report may include a classified annex.