David Davis has criticised the EU for publishing a paper with proposals to restrict Britain's access to the single market during the Brexit transition period.
An EU document was leaked yesterday suggesting any dispute during the two-year transition period could lead to sanctions against the UK.
The Brexit secretary said the move to publish the proposals was "not in good faith".
"I do not think it was in good faith to publish a document with, frankly, discourteous language and actually implying that they could arbitrarily terminate in effect the implementation period," Davis said.
"That's not what the aim of this exercise is, it's not in good faith and we think it was unwise to publish it."
Davis was speaking after a two-day meeting of the Brexit war Cabinet in which ministers thrashed out the UK's position on transition and trade after Brexit. He said the atmosphere had been "very constructive" but there was "still progress to be made".