Former US president Barack Obama has launched a strong critique of his successor Donald Trump, calling him "the symptom, not the cause" of division and polarisation in the United States..
Trump is "just capitalising on resentments that politicians have been fanning for years", the former president said during a speech at the University of Illinois.
Obama was accepting an ethics in government award at the university on Friday.
Noting the history of former presidents avoiding the rough and tumble of politics, Obama acknowledged his sharp critique of Trump was something of a departure from tradition.
But he said the political moment required a pushback and called for better discourse.
"Appealing to tribe, appealing to fear, pitting one group against another, telling people that order and security will be restored if it weren't for those who don't look like us or don't sound like us or don't pray like we do - that's an old playbook," he said.
Former president Barack Obama said Donald Trump is "capitalising on resentment that politicians have been fanning for years". Source: Getty Images
"It's as old as time. And in a healthy democracy, it doesn't work. Our antibodies kick in and people of good will from across the political spectrum call out the bigots and the fear-mongers and work to compromise and get things done and promote the better angels of our nation."
The remarks were his first steps into the political fray ahead of the autumn campaign for the US midterm elections.
While Obama has endorsed candidates and appeared at fundraising events, he has previously spent much of his post-presidency on the political sidelines.
But in unusually direct terms on Friday he made clear his concerns about politics in the Trump era, and implored voters - especially young people - to show up at the polls in the November elections.
"Just a glance at recent headlines should tell you this moment really is different," Obama said.
Trump: 'I fell asleep'
"The stakes really are higher. The consequences of any of us sitting on the sidelines are more dire."
He later added: "This is not normal."
Trump fired back, saying he went to sleep watching the speech.
"I'm sorry, I watched it, but I fell asleep," he said at a campaign appearance in Fargo, North Dakota.
"I found he's very good for sleeping," Trump added.
Trump also said Obama was trying to take credit for this "incredible thing that's happening to our country".
He went to talk about economic gains since he took office.
On Saturday, Obama will stump for Democratic candidates from California at an event in Orange County, a conservative-leaning part of California where Republicans are at risk of losing several congressional seats.
Next week, he plans to campaign in Ohio for Richard Cordray, the Democratic nominee for governor, and Ohio Democrats.
Obama's campaign activity will continue through October and will include fundraising appearances, according to an adviser.
