(QHA) -

A ship carrying the Russian sailors who have been training for months on a French-built Mistral helicopter carrier left the French port of Saint-Nazaire on Thursday, France 24 reports.

It remains unclear if France will ever fulfill its contract with Russia.

The sailors have been training since June on board the “Vladivostok”, one of two Mistral-class helicopter carriers adapted for the Russian navy according to the terms of a €1.2 billion ($1.58 billion) deal signed in 2011.

The deal has been subject to months of intense deliberation, with Paris coming under intense pressure from its NATO allies to scrap delivery of the ships due to Russia’s alleged involvement in the Ukrainian crisis.