Germany’s chancellor, Friedrich Merz, will meet the European Commission chief, Ursula von der Leyen, and Belgium’s prime minister, Bart De Wever, for emergency talks on Friday as the EU races to save its sorely needed financing plan for Ukraine.

The three leaders will dine in private in Brussels, a German government spokesperson said on Thursday, as Belgian officials continued to express strong opposition to the scheme, which involves the unprecedented use of frozen Russian assets.

With Russia’s attacks intensifying, Washington pushing for a peace deal that favours Moscow and Kyiv fast running out of money and Europe struggling for influence at US-led talks, the bloc must find a solution or suffer a major blow to its credibility.

Two weeks before a crucial 18 December EU summit, von der Leyen on Wednesday proposed two main options for the EU to raise the tens of billions of euros Ukraine needs to keep funding its struggling military and basic services against Russia’s war.

The EU has pledged to keep Ukraine afloat next year. It aims to raise €90bn (£80bn) to meet about two-thirds of Kyiv’s needs for 2026 and 2027, von der Leyen said, giving Ukraine the means to negotiate a peace deal “from a position of strength”.

The bloc could either borrow against its shared budget on the international markets, the commission president said, or issue a loan secured by immobilised Russian assets – mainly held in Belgium – that Kyiv would repay from Russia’s postwar reparations.

There are, however, obstacles to both alternatives. Many member states are not keen on common borrowing, which would have to be repaid. It would also need unanimity, which may prove difficult given Hungary’s past opposition to funding for Ukraine.

The frozen assets plan, floated almost two months ago, continues to be fiercely rejected by Belgium, which hosts about two-thirds of the estimated €290bn of Russian assets held in the west at Euroclear, a securities depository in Brussels.

“This is quite a big moment,” a diplomat from a founding member state said. “It’s never easy to reach agreement at 27, we know that. But if we can’t do something as existential as funds for Ukraine, we’ll really have failed – both us, and Ukraine.”

The logic of using the assets as security for a huge loan to Ukraine – not confiscating them, which most experts agree would be illegal – is that it would show Moscow that Ukraine could keep fighting for years, putting Kyiv in a better negotiating position.

But De Wever’s government has repeatedly argued that should Russia decide to launch retaliatory legal action, or demand its money back because the sanctions against it have been lifted, it risks being left on the hook for billions, alone.

“We have the frustrating feeling of not having been heard. The texts the commission tabled do not address our concerns in a satisfactory manner,” Belgium’s foreign minister, Maxime Prévot, said on Wednesday, calling for joint EU borrowing instead.

De Wever, a Flemish nationalist, has gone further. The Belgian prime minister told an event in Brussels this week it was “a nice idea, stealing from the bad guy to give to the good guy. But stealing the frozen assets of another country has never been done.”

He added: “Even during the second world war, we did not confiscate Germany’s money. In a war, you freeze sovereign assets. And at the end, the losing side must give up all or part of those assets to compensate the victors.”

But, De Wever claimed, it was “a fairytale, a complete illusion” to “imagine that Russia will lose this war in Ukraine”. Moscow had “let us know that if the assets are seized, Belgium, and me personally, will feel the effects for eternity”.

The commission has insisted the plan complies fully with EU and international law and a “three-tier defence” would shield Belgium from legal jeopardy, an argument von der Leyen and Merz are likely to advance at Friday evening’s dinner.

In an op-ed in the Frankfurter Allgemeine Zeitung newspaper on Thursday, the German chancellor warned his fellow EU leaders that the decisions they made over the coming days would “decide the question of European independence”.

An “imperialist Russia” was “striving to extend its sphere of influence into the states of Europe” and “preparing militarily for a conflict with the west”, Merz said, adding that it was vital to “send an unambiguous signal to Moscow” by using the assets.

He said Belgium should be given assurances the risks of the plan would be borne fairly by all EU member states, with each country “incurring an equal share of the risk, as a function of their respective economic performance”.

Europe must “decide and shape what happens on our continent”, he added. “The financial resources of an aggressor have been lawfully frozen within the jurisdiction of our constitutional state. What we decide now will determine the future of Europe.”