European Union leaders on Thursday condemned the "unspeakable suffering" Russia was inflicting on Ukraine but at a summit in France they refused Kyiv's appeal for rapid accession to the bloc and differed over the reach of sanctions against Moscow.

The Russian invasion - the biggest assault on a European state since World War Two - has upended Europe's security order and spurred EU capitals into rethinking what the bloc should stand for, its economic, defence and energy policies.

The EU was swift in imposing sweeping sanctions and offering political and humanitarian support to Ukraine, as well as some arms supplies, in the days after Russia attacked on Feb.24.

However, cracks have appeared in the bloc's united front, from its reaction to Kyiv's demand for an accelerated membership of the wealthy club to how fast it can wean itself off Russian fossil fuels and how best to shape an economic response.

"Nobody entered the European Union overnight," Croatia Prime Minister Andrej Plenkovic said as talks among the 27 national leaders ended at wee hours on Friday.

The leaders chairman, Charles Michel said in a show of sympathy and moral support: "Ukraine belongs to the European family."

But others made clear Ukraine would not be allowed to join hastily, something Ukrainian President Volodymyr Zelenskiy has sought and which has some support from Ukraine's neighbours on the EU's eastern flank.

"There is no fast-track process," said Dutch Prime Minister Mark Rutte, a prominent opponent of EU enlargement, while adding the bloc would continue deepening ties with Kyiv.

Nor could the door to accession be closed, said French President Emmanuel Macron.

"Can we open a membership procedure with a country at war? I don't think so. Can we shut the door and say: 'never'? It would be unfair. Can we forget about the balance points in that region? Let's be cautious."

Joining the EU is a process that usually takes years and requires meeting strict criteria from economic stability to rooting out corruption to respecting liberal human rights.

RUSSIAN OIL AND GAS

Russia's invasion, which Moscow calls a special military operation, has shattered Europe's post-war security order that emerged from the ashes of World War Two and the collapse of the Soviet Union in 1991.

More than 2 million people have fled the country, thousands of civilians have been killed, and Russian President Vladimir Putin's troops laid siege to several Ukrainian cities.

"It is a war crime," Roberta Metsola, president of the European Parliament, told the leaders.

Some EU leaders pushed for tougher sanctions that would hit Russia's oil and gas industries even if that meant repercussions for those European nations reliant on Russian fossil fuels.

Latvian Prime Minister Krisjanis Karins, whose country shares a border with Russia, said cutting off Russian oil and gas would be the most effective way to get Putin to the negotiating table.

"We should go much further and much faster," Karins said.

German Chancellor Olaf Scholz did not comment on whether the bloc should ban Russian oil imports, which Berlin has ruled out so far. Russia supplies about a third of Germany's gas and crude requirements.

But the EU should stop using Russian fossil fuels by 2027, von der Leyen said, adding she would propose a roadmap for that in mid-May.

The leaders resume at 0900 GMT on Friday to consider policy to tackle defence and energy spendingrelated to the war in Ukraine. Divisions have emerged over the possibility of a new joint EU debt issuance, advocated by countries like France and Italy but opposed by Germany, the Netherlands and others.

"The war in Ukraine is an immense trauma... But it is also most definitely something which is going to lead us to completely redefine the structure of Europe," said Macron.

Reuters