EU leaders vowed to find the money to cover Ukraine’s financing needs at a summit in Brussels on Thursday, even as Belgium restated its unwavering opposition to using Russia’s frozen assets.

The bloc is seeking to use €210bn in Moscow’s sovereign assets held in Euroclear, the central securities depository based in Belgium, to guarantee a €90bn loan to Kyiv over the next two years. The money is intended for Ukraine to fend off Russian aggression and ensure Europe has a key role in US-led peace talks despite Russia threatening a “harsh” legal response.

EU officials said ahead of Thursday’s summit in Brussels that they were hopeful of a deal even if it meant meeting through the night. The summit is scheduled to end on Friday but could be extended. European Council president António Costa vowed that leaders would “never leave” the summit until an agreement was struck.