The conditions for the transfer of the first Mistral-class helicopter carrier by France to Russia have not yet been fulfilled, French Foreign Minister Laurent Fabius has said.

"The terms for this delivery have not yet been met. It is absolutely clear," he told the France Inter radio station.

"There are totally obvious reasons behind all this. It will be enough to take a look at what is going on in Ukraine," Fabius said.

The deadline for the transfer of the Mistral-class ships is set by the contract, the minister said.

"There are contractual obligations, which I won't speak about here," he added.