In his farewell speech in Chicago, President Barack Obama has called on Americans to defend their democracy.

He told thousands of supporters: “By almost every measure, America is a better, stronger place than it was eight years ago.”

However, Barack Obama warned “democracy is threatened whenever we take it for granted”.

The incumbent president implored Americans of all backgrounds to consider things from each other’s point of view, saying “we have to pay attention and listen”.

Barack Obama, who is America’s first black president, was first elected in 2008 on a message of hope and change.

His successor, Donald Trump, has vowed to undo some of Barack Obama’s signature policies.

Photo White House

Donald Trump will be sworn into office on Friday, January 20.

Raucous chants of “four more years” from the crowd were brushed aside by the president.

“I can’t do that,” Barack Obama said with a smile. US presidents are limited to two terms by the constitution.

“No, no, no, no no,” he said, when the crowd booed the prospect of Donald Trump replacing him.

Striking an upbeat tone, Barack Obama said that the peaceful transfer of power between presidents was a “hallmark” of American democracy.

However, Barack Obama outlined three threats to American democracy – economic inequality, racial divisions and the retreat of different segments of society into “bubbles”, where opinions are not based on “some common baseline of facts”.

“If you’re tired of arguing with strangers on the internet, try to talk with one in real life,” he said to laughter and applause.

In his closing remarks, Barack Obama said he had one final request for Americans as president: “I am asking you to believe. Not in my ability to bring about change – but in yours.”

Returning to Chicago, where he first declared victory in 2008, Barack Obama delivered a mostly positive message to Americans after a divisive election campaign which saw Donald Trump defeat Democrat Hillary Clinton.

Barack Obama said that young Americans – including those who worked on his campaigns, and who believe “in a fair, just, inclusive America” – left him feeling “even more optimistic about this country than I was when we started”.

In choosing Chicago, Barack Obama had earlier said he wanted to return to “where it all started” for him and First Lady Michelle Obama, instead of delivering the speech from the White House.

Barack Obama said that it was in Chicago as a young man, “still trying to figure out who I was, still searching for purpose in my life”, that he “witnessed the power of faith and dignity of working people in the face of struggle and loss”.

“This is where I learned that change only happens when ordinary people get involved and they get engaged and they come together to demand it,” he said.

“After eight years as your president I still believe that.”

Some 18,000 people attended the farewell address at McCormick Place, the largest convention centre in North America and the venue for Barack Obama’s speech after he defeated Mitt Romney in the 2012 election.

The tickets were given out free, but were selling online for more than $1,000 each hours ahead of the speech.

As he leaves the Oval Office, President Barack Obama is viewed favorably by 57% of Americans, according to an Associated Press-NORC Center for Public Affairs Research poll, a similar level to Bill Clinton when he left office.