French President Francois Hollande said Thursday the conditions were "still not right" to go ahead with the sale of two Mistral warships to Russia despite Moscow having backed a new Ukraine peace plan.

Hollande suspended the 1.2 billion euros ($1.5 billion) sale last year as the Ukraine crisis deepened, fearing it would boost Russia's military capabilities and put Paris in hot water with its allies.

Fresh from negotiating a new Ukraine ceasefire in the Belarus capital Minsk, Hollande said that if the accord was implemented in full, then the situation could change.

"I hope that will be the case, one day," the president told reporters after a European Union summit dominated by discussion of the latest Ukraine peace plan.

"It is clear that if everything falls into place, then measures will be taken at the European level to ease sanctions" imposed against Russia over its intervention in Ukraine, he said.

"France would be part of such a process but for the moment we are not there yet," Hollande added.

France delayed delivery of the first vessel due in November and then postponed it "until further notice."

Moscow promptly warned it would demand costly compensation if the sale was cancelled outright and the deal has been in limbo ever since.

In December, Russian sailors training to operate the Mistrals -- each of which can carry 16 helicopters, four landing crafts, 13 tanks and over 400 soldiers -- left France.