France will not move ahead with the delivery of the first of two Mistral amphibious assault ships to Russia because of Russia’s involvement in the conflict in Ukraine, the office of President François Hollande said in a statement Wednesday. Hollande had been under pressure from allies to suspend or cancel the delivery of the ships. 

“The president of the republic has concluded that despite the prospect of cease-fire, which has yet to be confirmed and put in place, the conditions under which France could authorize the delivery of the first helicopter carrier are not in place,” the French presidential statement read.

Western sanctions on Russia over the Ukrainian crisis do not cover the contract for the two ships worth $1.6 billion, but Hollande noted ahead of a NATO meeting on Saturday that “there are new decisions to be taken” in light of NATO and U.N. accusations that Russia directly intervened on behalf of pro-Russian rebels fighting the Ukrainian government. NATO Secretary-General Anders Fogh Rasmussen said on Monday that NATO would not seek to block the transfer of the two ships ordered by Moscow and the decision was up to the French government.

Russia and France signed the contract for the two helicopter carriers in 2011. France resisted EU moves to impose an arms embargo on Russia that would block the sale of the ships in March. The first carrier, Vladivostok, is completed and was set to be in Russia by the end of this year. The second ship, Sevastopol, was to be delivered by the end of 2015. Russian sailors have been training on the Vladivostok since June.

British Prime Minister David Cameron said in July it would be "unthinkable" for the U.K. to continue on with such a deal with Russia amid the Ukraine crisis. President Barack Obama said he thought "it would have been preferable to press the pause button" on the deal.

Each Mistral-class ship has a crew of 170 and can operate 16 helicopters. Around 400 Russian sailors have been training on the Vladivostok since June. Russia has paid for the first ship, but plans to pay for the second on delivery.