Alex Ritson

Polish Prime Minister Donald Tusk said European leaders had a straightforward decision to make.

Our correspondent James Waterhouse in Brussels explained what's at stake.

At its heart is a proposal to unfreeze tens of billions of euros worth of frozen Russian assets to support Ukraine in the form of a loan.

Kyiv has a gaping hole in its finances over the next couple of years to the tune of 135 billion euros.

Volodymyr Zelensky acknowledges that this proposal is crucial for his country's survival and those in support of it, like Germany, like the European Commission, like the UK, like France, say this is crucial for Ukraine to survive long enough for a lasting peace deal.

But there are growing opposers to this idea, not least with Belgium, where the majority of this Russian money is kept.

There are fears of legal reprisals, which have been promised by Moscow.

So what is clear is that there are going to be some very long, drawn-out negotiations today.

A plan B is being touted that could see Europe support Ukraine through its debt, through widening its debt and incorporating it into its budget.

But that requires unanimous support, which is almost certainly not going to happen.

So this is a crucial juncture if you consider where we are in the peace endeavours to try and end the war in Ukraine.

From the European perspective, why is using Russian money, European leaders generally see Russia as the aggressor in this war, why is that controversial?

Because if you are Belgium, for example, and you are hosting 200 billion euros worth of Russian cash, you are worried about being legally compelled to pay Moscow back once the war is over.

Now, what Europe is saying is, well, there's no legal mechanism for that.

It's not going to recognise Moscow's courts.

And it's also saying that it would spread the risk.

But even Euroclear, which is the institution which houses this cash in Belgium...

It has its own frozen assets inside Russia, so it's about vulnerability.

And to boot, there is also another concern here, which is that America has been lobbying European members to block it as well, because there have been previous proposals leaked that shows Washington wanting to get its own hands on this cash for future investments with Russia.

So there are a lot of forces at play here.