"We are certainly approaching a moment in our Europe where it will be appropriate not to be a coward," Macron told French expats living in Prague.

Macron faced a backlash from many Western allies after he openly discussed the idea of sending Western troops to Ukraine at a Paris-based conference on Ukraine on Feb. 26.

In a reference to Russia's invasion of Ukraine, Macron said on Tuesday that France and the Czech Republic were "well aware that war is back on our soil (in Europe), that some powers which have become unstoppable are extending every day their threat of attacking us even more, and that we will have to live up to history and the courage that it requires."

Macron did not elaborate on this.

Macron's Feb. 26 comments, made after he hosted a meeting of Western leaders to rally support for Ukraine, fitted with his reputation as a diplomatic disruptor who likes to break taboos and challenge conventional thinking.

French officials were later sent out to explain that Macron had wanted to stimulate debate and that ideas under discussion involved non-combat troops in roles such as demining, border protection or training Ukrainian forces.

During his Prague visit, Macron is also expected to discuss support for plans announced last month by the Czech Republic, backed by Canada, Denmark and others, to finance the rapid purchase of hundreds of thousands of ammunition rounds from third countries to dispatch to Ukraine.

Ukraine is critically short of artillery rounds as its troops try to hold back Russian forces who are again on the offensive in the east, two years after Moscow launched its full-scale invasion.

Macron suggested on Feb. 26 that Paris would contribute to the Czech initiative, without clarifying how.

One of the key issues for France has been how such an initiative would be financed given that it has long pushed for the EU to use European financing only for the European defence industry and opposed the idea of using European money to buy outside the bloc.

Despite Macron's apparent support for the Czech initiative, several French diplomats said Paris remained opposed to using European money, but supported the idea of bilateral purchases.

"I would not like to leave you hoping for a French reversal of position on the question of the European defence industrial base," one diplomat said.

"We know, like the Czechs, of the need to acquire as much ammunition as possible for the benefit of the Ukrainians, but without it fundamentally changing our vision which is that European resources must allow the European industry to gain strength," the diplomat said.

(Writing by Ingrid Melander and John Irish, Editing by William Maclean)