German Chancellor Angela Merkel | Christof Stache/AFP via Getty Images UK must pay Brexit bill, says Angela Merkel German chancellor said bill was not a fine but an ‘obligation’ that Britain had entered into.

German Chancellor Angela Merkel warned the U.K. on Saturday that it would have to pay a settlement to leave the EU, denying that the obligation amounted to a “fine.”

“This is about obligations that Great Britain has entered into and that naturally must remain on the books,” Merkel said in her weekly podcast published Saturday ahead of the latest round of talks next week, Bloomberg reported. “It’s not about the cost of divorce — that makes it sound like fines. We’re still at the very start of these negotiations.”

The divorce bill, or how much the U.K. should pay the EU upon leaving the bloc, is one of the most contentious issues in the Brexit talks. The EU has already outlined a full list of bodies and funds that it believes must be covered by the financial settlement. Estimates of the bill have ranged up to €100 billion.

Brussels has told Britain to come forward with a proposal for how to calculate the bill or risk derailing next week’s Brexit talks — something it has so far declined to do, preferring to critique the EU proposal.

Boris Johnson, the British foreign secretary, said he did not “recognize” the €100 billion figure but added that “we should pay not a penny more, not a penny less, of what we think our legal obligations amount to.”