After being urged for months by fellow Western leaders to cancel the sale of an amphibious assault ship to Russia, France’s president François Hollande on Wednesday said the ship’s transfer had been suspended.

In a terse statement that was released on the president’s website, Hollande said “the conditions that will allow France to authorize the delivery of the first amphibious landing ship have so far not been met.”

Earlier, Hollande had suggested that only the sale of a second Mistral warship could be canceled if the European Union decided to expand its sanctions against Russia. “That will depend on Russia’s attitude,” he said in July.

At the time, the Socialist Party leader, who is France’s least popular postwar president, maintained that the first ship, named Vladivostok by the Russians, was already paid for and sanctions could not be applied retroactivity. The ship was due to be delivered next month.

What “conditions” Russia had failed to meet was unclear. But Western countries accused it last week of sending troops directly into Ukraine, marking a further escalation in Russia’s conflict with both the former Soviet republic and its former Cold War rivals.

Russia still denies it supports a separatist uprising in the east of Ukraine although satellite images released by NATO late last month showed Russian artillery units crossing the Ukrainian border while Russian soldiers were apprehended in the country.

Before Russia intervened last week, the insurrection had been driven back by the Ukrainian army into the cities of Donetsk and Luhansk and seemed on the verge of collapse. Then the rebels opened a new front in the direction of Mariupol. From there, Russia could establish an overland connection with the Black Sea peninsula of Crimea it took from Ukraine in March.

The second Mistral warship France was due to sell Russia had been christened Sevastopol, after the Crimea’s largest city and headquarters of Russia’s Black Sea Fleet.

France’s €1.2 billion euro contract for the two Mistral ships — which can carry up to sixteen helicopters and sixty armored vehicles each — was signed by the government of Hollande’s conservative predecessor, Nicolas Sarkozy, in 2011. It was the first military hardware sale by a NATO ally to Russia since the collapse of the Soviet Union in 1991 and had seemed to mark a normalization in East-West relations.