According to the official reports, upping the stake in an already highly contested contract, Russian Prime Minister Vladmir Putin has made the purchase of NATO ships from France conditional to Paris' provision of high-tech warship technology.

France, in return, is vying for a bigger chunk of Russia's oil and gas business.

The contentious issues were discussed between Putin and French President Nicolas Sarkozy during a visit by the Russian government leader to Paris on Friday.

No breakthrough was announced on either side but the French president's office said both leaders agreed that a "a pending deal to build four Mistral-class warships would be a 50-50 project."

The deal, if clinched, along with rights to construct several other vessels of the same class in Russia, would mark the most important transfer of military equipment to Russia by a NATO member country.

Designed to attack the shore from the sea, the Mistral class is viewed as an ideal weapon for Russia against possible uprising by nearby countries.

It was also reported that aside drawing pressure from those neighboring states and the United States, the potential contract faces serious obstacles of its own.

France 24 reported that Moscow was adamant on its conditions for the transfer of technology and the building of such vessels on Russian soil.

The French news medium reported, "Paris has refused this condition and has stipulated that construction takes place in France."

Putin was quoted saying by French media on Friday, "The world is going through a difficult time and we have to stand together to remain competitive. In scientific and technological areas, we must unite our efforts." (With Inputs from Agencies)