The U.K. and France are among a number of EU countries that opposed a proposed classification system for green investments over concerns of potential reduction in the financing of nuclear and coal projects, on which some states heavily rely, EU officials told Reuters.

The other countries opposed to the framework, known as the taxonomy, were the Czech Republic, Slovenia, Hungary, Slovakia, Romania, Bulgaria and Poland, according to the report.

The rules help define which financial products should be classified as sustainable and green and do not explicitly exclude nuclear investments but would make it harder to label such funding as green, Reuters noted.

The countries voiced their opposition to the measure at a meeting of EU diplomats on Dec. 11, the same day the European Commission unveiled a slate of climate-related policy proposals including a €100 billion funding mechanism aimed at helping eastern European states that still rely heavily on fossil fuels.

The opposition came after the European parliament, council and commission reached a compromise agreement on the matter after several months of discussions, excluding coal and nuclear.

New negotiations will now have to be agreed, most likely in the week of Dec. 16, a French diplomat told Reuters.