EU leaders will find a solution to the problem of how to get money to Ukraine but must stay on the right side of the law, European Central Bank President Christine Lagarde said Thursday.

Addressing a press conference in Frankfurt after the ECB’s Governing Council meeting, Lagarde said she was “confident” that heads of government meeting in Brussels would thrash out a mechanism for lending to Kyiv, but immediately warned against expecting the ECB to underwrite it.

“We are an area of the world which praises itself for respecting the rule of law,” Lagarde said. “I’m sure that there are solutions that can be debated and discussed, and … constructions that can be elaborated, but it’s not for the central bank to actually encourage [or]support a mechanism under which we would be called upon — and scheduled — to breach Article 123 of the Treaty.”

Article 123 of the Treaty on the Functioning of the European Union forbids the ECB from printing money explicitly to finance government spending, which is what an EU loan to Ukraine would represent.

EU leaders are trying to put together a loan package that would be secured against Russian sovereign assets currently frozen at the Euroclear depository in Belgium. Russia has threatened legal action if it goes ahead, and Belgium has refused to back the EU’s proposal, for fear of being left on the hook for the legal liability. In that context, various reports have suggested that leaders have leaned on the ECB to “backstop” the loan with guarantees of its own.

“You cannot expect me to validate a mechanism under which there would be monetary financing,” Lagarde said. “This is pretty obvious.”