While the European Union must drastically reduce its CO2 emissions to combat climate change, "it is obvious that we need more renewable and clean energy," she said at the end of a summit of the bloc's 27 members.

Renewables such as wind and solar have tumbled in cost and do not depend on imports, she told a press conference, adding that they will offer "a lot of independence" to the EU.

However, alongside renewables "we need a stable source, nuclear; and during the transition, of course, natural gas", the head of the European Union's executive body said.

Nuclear power plants have the advantage of emitting almost no CO2 into the atmosphere, while gas -- the least polluting major hydrocarbon fuel -- provides a stop-gap fuel source while alternatives are developed.

The European Commission must propose before the end of the year its so-called green taxonomy -- a list of energies considered beneficial for the climate.

This will open up access to green finance that will give these technologies a crucial competitive advantage.

"Never before has such clear and broad support been expressed for the need to use nuclear energy to achieve our climate goals," French President Emmanuel Macron said on Friday.

France, which gets about 70 percent of its power from nuclear and is a major exporter of electricity, is preparing to restart construction of atomic power plants.

"A very large majority of member states" wanted to include both gas and nuclear in the taxonomy, a European diplomat told AFP on Thursday evening. Two other officials confirmed the level of support.

In the context of the current gas price crisis 10 EU states, led by France, published a statement in mid-October supporting nuclear power.

But other countries, including Germany, Austria and Luxembourg, are fiercely opposed, pointing to the problem of very long-term storage of radioactive waste.

At the beginning of October, Commission Vice-President Valdis Dombrovskis, defended nuclear power at a meeting of EU finance ministers, calling for recognition of its role "as a low-carbon energy source in our effort" to reduce emissions.