The latest version of the European Union's proposal for financial support for Ukraine is the closest to compliance with international law, said ECB President Lagarde.

EU leaders have been discussing for several months how to use frozen Russian assets to finance Ukraine, while staying within the framework of international law, which prohibits direct confiscation.

"The scheme that has been developed and will be discussed at the upcoming European Council meeting is the closest to compliance with the principles of international law of all that I have seen," Lagarde said at the Financial Times event.

"It is our duty as Europeans to continue to support, protect, and act in the interests of Ukraine," Lagarde added.

Lagarde, who does not play a direct role in this process, has long expressed concern about the use of Russian assets and notes that the ECB insists on compliance with international law in any outcome, otherwise the global reputation of the euro could suffer.

"This is a very, very exceptional case, and it does not deprive Russia of ownership of the assets," she said of the current proposal.