At a summit in Brussels, the leaders also talked with NATO boss Jens Stoltenberg and discuss what role the EU could play in Western commitments to bolster Ukraine’s security.

"It will definitely come up," she told reporters in Brussels on the eve of the two-day summit, a regular gathering that will also discuss migration, relations with China and other issues.

Like several other EU leaders, Kallas said the mutiny showed cracks appearing in Russia’s leadership. She said she had seen different views on how the mutiny could affect the Ukraine war and the risk Russia poses to the West.

The West should not be swayed and continue to support Ukraine and bolster its own defences, Kallas said.

Charles Michel, the president of the European Council of EU leaders, struck a similar note.

"Ever more in these circumstances, we will reassert our commitment to support Ukraine for as long as it takes, including through sustainable financial and military assistance," he wrote in a letter inviting leaders to the summit.

SECURITY PACKAGE

The nature of that assistance will also be on the table in Brussels as Western countries work on a package of long-term assurances to provide weapons, equipment, ammunition, training and other military aid to Kyiv.

A draft of the summit conclusions said EU countries were ready to contribute to future security commitments to Ukraine, to "help Ukraine defend itself in the long term, deter acts of aggression and resist destabilisation efforts".

Diplomats said the text had been proposed by France, a champion of a greater military and security role for the EU.

Diplomats from some countries said they wanted more details and were concerned the idea may conflict with efforts involving the United States and NATO on long-term commitments to Ukraine.

“There are many questions for many member states,” said a diplomat from one EU country.

Countries including the US, Britain, France and Germany are discussing such measures ahead of a NATO summit next month in Vilnius, Lithuania, where Ukraine’s long-term security will be a major theme.

France has insisted any EU contribution would dovetail with those made by others and build on existing EU initiatives.

These include the European Peace Facility, a fund that reimburses EU members for military donations to Kyiv, and a training mission for Ukrainian soldiers.

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