BRUSSELS — European governments are accusing Belgium of making excessive demands for “blank check” protection in case the Kremlin sues over the deployment of €140 billion of frozen Russian assets held in Brussels.

The governments’ reluctance could derail negotiations on an EU plan to lend those immobilized assets to Ukraine ahead of a crunch summit in December.

The European Commission is on the verge of unveiling the legal framework for the loan in a race against time to ensure Ukraine’s war chest doesn’t run bare in April. EU leaders will have their say when they meet in mid-December.

“We are advancing our work to meet Ukraine’s financial needs,” Commission President Ursula von der Leyen posted on X on Monday. “We have made good progress, and we plan to table our legal proposals this week.”

The so-called reparations loan is hugely contentious with Belgium’s government, as it would use the cash value of frozen Russian state assets on Belgian soil to finance Ukraine.

Amid fears of Russian retaliation, Belgian Prime Minister Bart De Wever insists that EU governments give Belgium cover with financial guarantees that exceed the €140 billion and that can be paid out within days. He also wants the lifespan of these guarantees to outlast the EU’s sanctions against Russia.

While European governments are open to guaranteeing a pre-agreed figure, they are reluctant to sign up to what they describe as a “blank check.” Four EU diplomats told POLITICO that they cannot accept De Wever’s request because it would put their country’s financial viability at the whim of a court ruling — potentially exposing them to billions of euros of repayments years after the war in Ukraine ends.

“If [the guarantees] are infinite and without limits, then what are we getting ourselves into?” said an EU diplomat who, like others quoted in this story, was granted anonymity to speak freely. The question of how comprehensive the national guarantees should be is shaping up to be among the hardest in the negotiations.

“For many member states, it’s politically difficult to give this blank check,” said a second EU diplomat. They cautioned, however, that it is unlikely that those safety nets will ever be used because the EU’s scheme is legally safe.

In order to secure political buy-in, the Commission has shown some EU ambassadors sections of its legal proposal — but the specific amount of the guarantees was left blank.

If there is no progress, the most likely alternative is to issue more EU debt to cover Ukraine’s budget shortfall. But the idea is unpopular among most EU governments because it involves using taxpayer money.

Speaking to reporters on the margins of a meeting of EU defense ministers on Tuesday, the EU’s foreign policy chief, Kaja Kallas, showed understanding for Belgium’s predicament — but fell short of suggesting a way forward.

“I don’t diminish the worries that Belgium has, but we can address those, shoulder those and work on a viable solution,” she said.