"It's not just warfare, it's also about how the war is conducted, the training of the soldiers," EU foreign policy chief Josep Borrell said after the talks.

"There are many training initiatives but the needs are enormous. We need to ensure the coherence of these efforts.

"All member states agreed clearly on that and on launching the work necessary to define the parameters for an EU military assistance mission for Ukraine," he said.

Borrell, who co-hosted the meeting together with the EU's Czech presidency, proposed the training operation last week.

Few details were disclosed but Borrell said the Ukrainian soldiers battling a Russian invasion since February 24 should be trained in nearby EU member states.

"It's clear that we have to be quick and ambitious," Borrell said.

But some ministers had sounded lukewarm before the meeting.

"It remains to be seen whether this is the right way to help," said Luxembourg Defence Minister Francois Bausch. "I am not so convinced."

"Perhaps it can be done more quickly and flexibly on a bilateral level under the coordination of the EU," he added.

Austrian Defence Minister Klaudia Tanner echoed his concerns.

"The first question to be clarified is whether such a mission can exist at all," she said, adding that similar missions had previously taken place outside the EU.

"From our point of view, many questions remain unanswered," Tanner said.

Backing the plan, Slovak Defence Minister Jaroslav Nad said his country was ready to host the training.

"I believe we will find a solution," he said.

Dutch Defence Minister Kajsa Ollongren said her country would "respond very favourably" to Borrell's plan.

"We are already training Ukrainian soldiers in the United Kingdom," she said.

"We are (also) working with Germany on new training on demining so we feel this is the right step to take," Ollongren said.