The Ban on Anti-Personnel Mines and Cluster Munitions – What Now?

In November 2025, Denmark’s centre-right parliamentary opposition proposed the country’s withdrawal from the 1997 Ottawa Convention and the 2008 Oslo Convention, which prohibit the use and stockpiling of anti-personnel mines and cluster munitions respectively. The proposal followed the decision by Estonia, Latvia, Lithuania, Poland and Finland to withdraw from the Ottawa Convention, with Lithuania also denouncing the Oslo Convention. Although the Danish government ultimately rejected the withdrawal proposal, the episode highlights the growing tension between these two disarmament treaties and new security realities.

This background paper does not seek to engage in the debate on the military utility of anti-personnel mines and cluster munitions. Rather, it examines the legal implications that the renewed focus on both types of weapons may entail, prompted by Russia’s war against Ukraine, in which both weapons are used extensively, and by the resulting deterioration of the security situation in Europe. It first outlines the relevant international legal framework governing anti-personnel mines and cluster munitions, including the obligations imposed by the Ottawa and Oslo Conventions, the general rules of international humanitarian law (IHL) as well as the Convention on Certain Conventional Weapons and its protocols. The paper then examines the rules governing treaty withdrawal from the Ottawa and Oslo Conventions, emphasising that denunciation is only available in peacetime and that it does not remove all legal constraints on the use of these weapons, particularly with regard to the protection of civilians.

The core focus of the paper, however, is the interoperability dilemma: the legal risks faced by States Parties to the Ottawa and Oslo Conventions when engaging in close military cooperation with allies not bound by these treaties. This dilemma is particularly acute in the Baltic region, where the defence of minefields along NATO’s eastern borders may become necessary. Only limited avenues exist for mitigating these legal risks, which is why Denmark and its allies should consider adjusting their obligations under the two conventions.

Such treaty modifications could take various forms. Removing the interoperability dilemma directly may appear to be the most straight-forward solution. Another option could be to narrow the scope of the prohibitions, for example by exempting certain non-persistent mines. While this may risk weakening the humanitarian ambition of the conventions, such a change might also enhance their continued relevance and encourage broader participation during a period of heightened geopolitical instability.