Which of the following actions is a characteristic of peace crimes?

The characteristic of peace crimes is best represented by acts that increase international crime and responsibility. Peace crimes are actions that typically undermine international peace and security and can include various forms of aggression or illegal conduct that negatively influence the global community.

In this context, the correct answer highlights how certain actions, especially those that do not align with the principles of maintaining peace, can lead to a broader responsibility for criminal behavior on an international scale. This aligns with the concept of accountability in international law, where acts that disrupt peace can have repercussions extending beyond the immediate parties involved.

Other options represent different concerns in the realm of international law and relations. Aggressive military actions and violations of a state's sovereignty can be serious, but they are more specific to the context of war crimes or violations of sovereignty rather than being classified as peace crimes. Engaging in diplomatic relations, while essential for maintaining peace, does not align with the framework of peace crimes, which focus more on actions that threaten or disrupt the peace rather than those fostering it.