Vladimir Putin has suggested David Cameron may have called a referendum on the EU "to blackmail Europe", in his first major intervention in the Brexit debate.
Politicians including Foreign Secretary Philip Hammond have speculated that Mr Putin would relish a Brexit as a way of weakening the European Union and allowing Russia greater scope to reassert itself.
Asked by the Press Association what his views on the looming vote are, Mr Putin suggested that the Prime Minister had called the referendum to "scare" Europe.
But the direct-speaking leader refused to be drawn over which side he supported - batting off attempts to ask him as a bid to make Russia a bogeyman.
Speaking in St Petersburg, Mr Putin said: "I don't think this is very proper to engage Russia in all the problems, even if we are not involved in it, to make Russia a scarecrow. Civilised people do not do things this way.
"As for the Prime Minister of the UK, there is a great problem with Brexit, why did he initiate this vote in the first place? Why did he do that? So he wanted to blackmail Europe or to scare someone, what was the goal if he was against?
"I want to say it is none of our business, it is the business of the people of the UK. I have my own opinion on this matter, I cannot talk about the result yet - no one knows about the result yet, I think it is 50-50 with a certain margin of error."
The Russian president appeared well-clued up on the domestic debates raging in Britain about the draw-backs of membership and its importance for the market.
He singled out controversial EU fishing laws as a particular bone of contention for some Britons.
But he refused to guess which way the vote will go on June 23.
He said: "Who can predict it? No one can predict it. I have my own opinion on this matter - whether it is good or bad - but I will refrain from giving the forecast. I think it would be improper on my part to do that.
"Whatever I say will be interpreted to the benefit of either side, that's the business of the EU and the people of the UK.
"Different experts have different estimates about whether Brexit will benefit Great Britain or not, some say it will be to the detriment and some say the EU will be more stable and stronger.
"In the UK itself for example - they are going down in boats saying how hard it is to live with restrictions in fishing. Yes they have a problem, well there are some benefits in other sectors. If you have to weigh all these things it is very complicated."
Most international political leaders who have spoken out about the EU referendum debate have urged Britain to stay, with US president Barack Obama and Chinese president Xi Jinping both imploring the UK to remain.
But political commentators in Britain have speculated that Mr Putin would rub his hands with glee if the vote was for leave on June 23.
Speaking at Chatham House on the topic earlier this year, Mr Hammond said: "None of our allies wants us to leave the EU - not Australia, not New Zealand, not Canada, not the US.
"In fact, the only country, if the truth is told, that would like us to leave the EU is Russia. That should probably tell us all we need to know."
Campaigning in the EU referendum has been suspended following the murder of Labour MP Jo Cox, who was shot and stabbed in the street outside her constituency surgery in Birstall, near Leeds in West Yorkshire.
Her death has shocked the world and prompted tributes from politicians around the world including Democratic presidential hopeful Hillary Clinton who said her death was "cruel and terrible".
It emerged on Friday that the EU was to extend some of its sanctions targeting Russia over its annexation of the Crimean peninsula for another year.
The announcement came one day after EU Commission President Jean-Claude Juncker met with Mr Putin in St Petersburg.
After the EU first imposed sanctions two years ago, Moscow retaliated by banning imports of meat, vegetable and dairy products from the EU, a blow to many of the bloc's members.
Mr Putin called on European leaders to improve ties with his country despite the sanctions.