France could renounce the sale of a second Mistral-class amphibious warship if EU leaders adopt tougher sanctions against Russia.

President Francois Hollande also announced it depended on "Russia's attitude" to the conflict in Ukraine whether the deal would be carried out, Bloomberg reported.

Commitments to Russia on the Mistral helicopter carriers cannot be entirely neglected, as arrangements had been made about the Vladivostok, a vessels already paid and to be delivered in October.

Made at his annual presidential press dinner, Hollande's comments came as European Union leaders are set to debate on a new round of sanctions targeting Moscow.

Talks follow allegations that pro-Russian rebels, reportedly backed by the Kremlin, downed a Malaysian Airlines passenger jet last week as it was flying over Eastern Ukraine.

All 298 people aboard the Boeing 777 died.

Russia argues Ukrainian planes had passed near the site where the aircraft was last in the air.

France, for its part, has long maintained it would not abandon the mistral deal, against the backdrop of EU-wide debate on the scale of restrictions that should be imposed on Russia over its position on Ukraine.

After French intentions to pursue the contract were criticized by US President Barack Obama back in June, UK Prime Minister David Cameron also slammed the project.

Cameron was quoted by the Moscow Times as saying the it was now "unthinkable" to fulfill such an order "like the outstanding one the French have".

German Chancellor Angela Merkel, on the other hand, believes it is only a decision to introduce economic sanctions that could prevent the deal.

Russia's Deputy Prime Minister Dmitry Rogozin, however, played down threats coming from Francois Hollande, casting a doubt the deal could be canceled.

So far the EU has stopped short of economic sanctions, with personal asset freezes and travel bans being the only adopted measures.