Poland is ready to start work on resuming the production of anti-personnel mines, its defence minister said on Thursday, after Warsaw joined the Baltic states this week in announcing a plan to withdraw from a treaty that bans their use.

But the ministers of Poland, Lithuania, Latvia and Estonia argue that the security situation along NATO’s eastern flank has “fundamentally deteriorated” since they signed on to the Anti-Personnel Mine Ban Convention, and that “military threats to NATO member states bordering Russia and Belarus have significantly increased.”