The article presents key issues related to the assertion of claims for liability for damages resulting from the instigation and conduct of a war of aggression. These issues have become topical again not only due to revival of the discussion concerning claims for damages caused during the Second World War, but also due to the ongoing armed conflict between the Russian Federation and Ukraine since 2021. At present, there are no codified, uniform and well-established legal principles in this area regarding the claims themselves in general, or for their enforcement. Under international law, a war of aggression can certainly give rise to an obligation to provide compensation on the part of the state that caused or conducted it (the responsible state).In the twentieth century, the issue of liability for reparations was primarily regulated in acts of peace-making, most famously in the Treaty of Versailles. However, there is still an ongoing theoretical discussion as to whether and how liability for damages can be effectively claimed by the injured state, but also by individuals – on the basis of the rules of international law or even domestic law, since these entities do not, in principle, have international legal subjectivity. Indeed, individual claims are or at least can also be the subject of international agreements. In this context, the article points to a trend away from the principle of absolute jurisdictional immunity of states in favour of limited immunity, which should also be applied to immunity from enforcement. This leads to the question of the desirability of moving away from rigid rules of protection for states when, by provoking and waging a war of aggression, they can on this basis avoid liability for their own unlawful actions. Furthermore, given the limited framework of legal instruments of influence in relations between states, the question arises as to whether and which measures (including the long-known so-called precautionary measures) can be used unilaterally not only against a state, but also against its citizens and the assets of the legal entities subject to its legislation. In practice, it is precisely such measures that can serve to secure claims for damages through the seizure of property assets. However, it should not be forgotten that the application of such unilateral measures may be challenged in relations between Member States of the European Union. In addition, any expropriation or confiscation may be challenged as inadmissible not only under the constraints of Article 215 TFEU, but also in light of the protective norms of the EU Charter of Fundamental Rights and Article 1 of Protocol No. 1 to the ECHR, and, at the level of state legislation, constitutional norms.