Two Mistral assault ships are to be sold to Russia, France's Foreign Minister Laurent Fabius announced.

The decision comes amid tensions between Moscow and the West over the Ukraine crisis.

Fabius wrote on Twitter that the contracts were agreed in 2011 and were to be executed as they would create many jobs in his country, as the BBC reported.

On his visit to France where he is attending D-Day commemorations, US President Barack Obama voiced his concerns over the sale and, though recognizing the deal was important for the French economy, said "it would have been preferable to press the pause button".

German Chancellor Angela Merkel has however backed plans of Paris to go ahead with the contract, stressing on Wednesday that only the adoption of "stage three" (or economic) sanctions against Russia could interrupt the delivery.

She was quoted by the EUObserver as saying the EU was not launching such measures because Russia did not stop the May 25 presidential election in Ukraine.

The deals signed between France and Russia on the two vessels are valued at EUR 1.2 B.

Under the existing agreements the Mistral-class amphibious assault ships, the Vladivostok and the Sevastopol, are to become part of the Russian Navy by end-2014 and 2015, respectively.