Donald Trump accuses Barack Obama of inaction over Russian involvement in 2016 election

Donald Trump has raised the stakes over Russia's alleged meddling in last year's presidential election by accusing his predecessor, Barack Obama, of failing to act.

Using Twitter, Mr Trump wrote “Since the Obama Administration was told way before the 2016 Election that the Russians were meddling, why no action? Focus on them, not T!”

In another tweet, Mr Trump quoted an Obama official as admitting that the administration had "choked" when it came to tackling the issue.

The Twitter onslaught was the latest development in the long-running controversy over Russia's role in the election.

It took a fresh twist on Friday when the Washington Post reported that Vladimir Putin was directly involved in the cyber operation to tilt the election against Hillary Clinton.

It also reported that Mr Obama was one of four people in the administration who was made aware of this, when he was sent a report by the CIA.

Russian hackers were blamed for the penetration of computers at the Democratic National Committee headquarters.

According to the Washington Post Mr Obama, who it says was made aware of Russia's role last August, debated how to respond with officials before deciding on expelling 35 diplomats and closing two Russian compounds.

Mr Trump's allies are hoping that the  Washington Post disclosures will ease pressure on his administration at a time when it is facing a series of investigations into alleged links between key campaign associates and the Kremlin.