U.S. President Donald Trump accused former President Barack Obama of "treason" on Tuesday, accusing him, without providing evidence, of leading an effort to falsely tie him to Russia and undermine his 2016 presidential campaign.

Besides Obama, President Trump on Tuesday rattled off a list of people he accused of acting criminally "at the highest level."

A spokesperson for Obama said that while the office “does not normally dignify the constant nonsense and misinformation flowing out of this White House with a response,” the Trump administration’s new “bizarre” and “ridiculous” allegations warranted one.