Britain’s chief Brexit negotiator, David Frost, said the U.K. and the European Union have made “very limited progress” toward a deal after the latest round of talks.

Frost warned that the two sides won’t be able to reach an agreement if the EU persists in its “novel and unbalanced proposals on the so-called level playing field,” he said in an emailed statement on Friday.

He also criticized EU demands for access to U.K. fishing waters, saying “we cannot agree arrangements that are manifestly unbalanced and against the interests of the U.K. fishing industry.”

Just one more round of talks remains before politicians meet in June to decide on the way forward, with both sides aiming to strike a deal around October. British Prime Minister Boris Johnson has repeatedly ruled out extending the deadline, raising the prospect of Britain ending its post-Brexit transition period on Dec. 31 without a free-trade deal, putting more pressure on an economy already reeling from the coronavirus pandemic.

The greatest obstacles to a deal remain the EU’s demands for a level playing field. These would keep the U.K. tied to some European rules, hampering its ability to undercut the bloc in areas such as taxation, state subsidies, workers’ rights and environmental standards. Britain says these aren’t justified and don’t reflect the country’s new status as an independent country. The EU argues that it can’t give generous access to its single market if it means the U.K. is prospering at its expense.

Britain says it isn’t arguing for anything other than a standard free trade agreement, such as the EU has struck with Canada, so it shouldn’t be forced into accepting other conditions.

The U.K will next week publish all its draft legal texts for the agreement, Frost said.

“We very much need a change in EU approach for the next round,” Frost said. “The U.K. will continue to work hard to find an agreement, for as long as there is a constructive process in being, and continues to believe that this is possible.”