French Foreign Minister Laurent Fabius let slip his irritation with Britain on Tuesday after London slammed its warship deal with Moscow, pointing out that the British capital was full of "Russian oligarchs."

The deal, under which France is selling two warships to Russia for €1.2 billion ($1.6 billion), comes at a time when the West has strong misgivings about Moscow's role in the Ukraine crisis, particularly after the downing of flight MH17 suspected of being targeted by pro-Kremlin rebels.

British Prime Minister David Cameron said Monday that "in this country it would be unthinkable to fulfil an order like the one outstanding that the French have."

When asked on French television about the controversy surrounding the contract, Fabius responded with a strong dose of sarcasm.

"The British in particular were very pleasant when they said 'we would never have done that'," he said.

"Dear British friends, let's also talk about finance. I was led to believe that there were quite a few Russian oligarchs in London."

Asked by the interviewer whether he was inviting the British to put their own house in order before making comments, Fabius said, "Exactly."

Fabius's anger will only have been strengthened on Wednesday after MPs said the UK was still exporting arms to Russia worth millions of euros.

A parliamentery committee said around 250 licences for the sale of arms to Russia, worth around €150 million remained in force, despite concerns Russia was arming rebels in Ukraine.

Following the report the Prime Minister's office said no arms had been sold to Russian forces since March.

French President François Hollande said on Monday that delivery of the first warship would go ahead in October as planned.

But Hollande said delivery of the second warship would depend on "Russia's attitude."

Washington also reiterates concerns

Britain is not the only country to have voiced concern about the deal.

On Tuesday, US deputy State Department spokeswoman Marie Harf told reporters delivery of the warships would be "completely inappropriate.

"We don't think anyone should be providing arms to Russia," deputy State Department spokeswoman Marie Harf told reporters, adding US officials had voiced their concern over the deal in recent days to the French foreign minister.

Asked what Washington thought about France going ahead with delivering the warships, Harf told reporters US officials "clearly think it's completely inappropriate. And we've told them they should not do it.

"We obviously don't think the Mistral should go ahead."

Per a 2011 agreement, France is to deliver two Mistral warships — an advanced helicopter assault ship — to Russia. The first is due in October 2014 and the second in 2015, and the contract is responsible for about 1,000 badly needed jobs in French shipyards.

"We've seen ample evidence that the Russians are flouting international norms, supporting efforts to violate the territorial integrity of independent sovereign nations," White House spokesman Josh Earnest said.

"It seems like a suboptimal time, if you will, to be transferring advanced military systems to them."