Slovakia’s Prime Minister Robert Fico warned that his country will oppose using Russian frozen assets to fund Ukraine’s defense spending, speaking with Slovakian public broadcaster STVR on Saturday.

“Slovakia won’t take part in any legal or financial schemes to seize frozen assets if those funds would be spent on military costs in Ukraine,” Fico said, Bloomberg reported, citing the interview with STVR.

The EU is trying to agree on a plan to use revenues from immobilized Russian assets to provide a €140 billion loan to Ukraine, without seizing the assets. The EU plan is crucial as the International Monetary Fund is concerned about Kyiv’s public finances, and even IMF aid depends on the EU’s support.

The European Commission is struggling to overcome concerns about the financial and legal risks the move could entail, especially from Belgium, where most of the frozen assets are housed. A meeting between EU and Belgian officials failed to find a deal on Friday, Euronews reported.

Views on whether the funds should be used for military costs also vary across the bloc.

Slovakia’s Fico has a track record of opposing the EU’s moves against Moscow and taking advantage of the leverage. He has threatened many times to block EU sanctions against Russia, trading his potential veto for concessions on other issues.

The EU plans to ensure the loan to Ukraine through EU countries’ guarantees and, in a second step, through a guarantee in the next EU budget, which would require unanimity. But other options, such as direct grants to Ukraine, are considered even less politically feasible.

EU leaders are set to discuss the issue at their December meeting.