Trump blames Obama after his obstruction of Russia probe threatens to bring down his attorney general
President Donald Trump. (Screenshot/Twitter)

President Donald Trump returned to a familiar strategy -- flinging blame at Barack Obama -- as the Russia investigation threatens to bring down his attorney general.

The president blamed Obama for failing to stop Russia from interfering in the 2016 election, which Trump has repeatedly denied took place, after reports showed special counsel Robert Mueller complained in a letter that Attorney General William Barr had mischaracterized his findings.

In fact, Obama asked congressional leadership to issue a bipartisan response to the Kremlin's election interference weeks ahead of the vote, but was rebuffed by Senate Majority Leader Mitch McConnell -- who threatened to turn the issue into a political weapon.

Mueller's report did not show evidence to charge Trump or his campaign associates with conspiracy with Russia, but it examined at least 10 instances of possible obstruction of justice by the president.

Barr has faced calls to resign after reports showed he misled Congress about Mueller's apparent frustration with his conclusions about the investigation, which he set down in writing in late March.