The European Union along with the Group of Seven (G7) countries have been discussing whether they could use the interest made on over 300 billion euros of immobilised Russian public money to fund Ukraine.
Over 200 billion of that amount is held in Europe with around 125 billion managed by Belgian clearing house Euroclear.
Euroclear declined to comment. Russia's central bank did not immediately respond to a request for comment.
The European Commission said in July it would present a proposal on whether there was a legally sound way to use the funds once the G7 agreed in principle. U.S. Treasury Secretary Janet Yellen said on Wednesday the Biden administration supported taxing windfall proceeds from these assets.
Belgium has already moved ahead on its own with its decision to use the tax paid on the interest. Brussels previously said in May, it would use 92 million euros it had already received in taxes.
"We only needed EU approval to use the interest. We are simply applying the Belgian tax code, which is our competence," a spokesperson for Prime Minister Alexander De Croo said.
Belgium expects to gather 625 million euros from 2023 tax revenues on frozen Russian assets and an estimated 1.7 billion euros in 2024.
"Last year, it was very clear to us that the taxation on the proceeds of those assets should go 100% to the Ukrainian population," De Croo told reporters earlier on Wednesday.
"That fund will be used for buying military equipment. We will do that in consultation; as well it will be used for humanitarian support."