Washington: In a fiery speech Saturday night, President Barack Obama said he would consider it “a personal insult” if the African American community does not turn out to vote in great numbers in November and help carry on his legacy by supporting Democratic nominee Hillary Clinton.

“If you care about our legacy, realise everything we stand for is at stake,” Obama, the nation’s first African-American president, said in an address to an annual dinner of the Congressional Black Caucus Foundation. “My name may not be on the ballot, but our progress is on the ballot.”

During his remarks to a packed ballroom at the Washington Convention Center — where Clinton preceded him at the lectern — Obama also mocked Republican nominee Donald Trump for advancing questions about the validity of his birth certificate and for claiming that this is the worst time to be a black American.

“He missed that whole civics lesson about slavery and Jim Crow,” a beaming Obama said, though he also acknowledged that African-Americans still face significant challenges.

“We do have challenges, but we’re not stupid,” Obama said. “We know the progress we’ve made.”

Obama began his remarks by saying, sarcastically, that he had “an extra spring in my step” given that Trump had finally acknowledged that he is an American citizen.

Trump, who for years advanced the notion that Obama was not born in the United States, sought to put the issue behind him this week by acknowledging the president’s citizenship — but instead reignited a firestorm by falsely claiming that Clinton sparked the controversy in 2008.

“And to think with just 124 days to go, under the wire, we got that thing resolved,” Obama said to laughter from the predominantly African American audience. “In other breaking news, the world is round, not flat.”

Obama’s remarks came at a time when polls have shown the race between Clinton and Trump tightening and amid concerns among Democrats that African-American turnout will not match what it was under Obama’s historic 2008 and 2012 elections.

Despite being battered all summer by his own missteps as well as a barrage of attack ads from Clinton, Trump has been surging in the battleground states in recent weeks.

“If I hear anybody saying their vote does not matter,” Obama told the crowd, “read up on your history. It matters. We’ve got to get people to vote.”

During her remarks, Clinton — who left the event before Obama spoke — paid tribute to the Democrat she is seeking to succeed, calling him “one of the best presidents this country has ever had.”

Clinton also made a couple of passing references to the birther controversy and was an award recipient at the dinner, picking up the organisation’s “trailblazer” award in recognition of her status as the first female presidential nominee of a major party in the United States.

“It’s not about golf promotions or birth certificates,” she said of this year’s race. “It comes down to who will fight for the forgotten, who will invest in our children, and who will really have your back in the White House.”

Saturday night marked Obama’s final appearance at the annual dinner. He joked that the “next time I show up I’ve got to buy a ticket.”