Speaking at his first public appearance in months, the former president warned that the current occupant of the White House was seeking to exploit people's fears about immigration to push forward his agenda.

Mr Obama's comments, made at a Democratic National Committee fundraiser, did not reference the president by name but spoke of his presidency, Politico reported.

"Fear is powerful," he said. "Telling people that somebody's out to get you, or somebody took your job, or somebody has it out for you, or is going to change you, or your community, or your way of life - that's an old story and it has shown itself to be powerful in societies all around the world," Mr Obama said.

"It is a deliberate, systematic effort to tap into that part of our brain that carries fear in it."

Mr Obama still carried his message of hope and optimism that saw him through two terms as US president, saying, "The majority of the country doesn't want to see a dog-eat-dog world where everybody is angry all the time.

He also framed tensions between Democrats and Republicans as "a fundamental contrast" world-view.

"They don't worry about inspiration," Mr Obama said. "They worry about winning the seat and they are very systematic about work not just at the presidential level but at the congressional and state legislative levels."

He added: "Do not wait for the perfect message, don't wait to feel a tingle in your spine because you're expecting politicians to be so inspiring and poetic and moving that somehow, 'OK, I'll get off my couch after all and go spend the 15-20 minutes it takes for me to vote.

"Because that's part of what happened in the last election. I heard that too much."

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