Washington: President Barack Obama urged the African-American community to help stop Donald Trump, saying he would consider it a "personal insult" to his legacy if black voters did not back Hillary Clinton.

"If I hear anybody saying their vote does not matter, that it doesn't matter who we elect -- read up on your history. It matters. We've got to get people to vote," Obama said on Saturday night while addressing the Congressional Black Caucus gala for the last time as president.

"I will consider it a personal insult -- an insult to my legacy -- if this community lets down its guard and fails to activate itself in this election. You want to give me a good sendoff? Go vote."

The President warned that while his name would not be on the ballot in the November 8 elections, all of the progress that the country has made over the last eight years was on the line, CNN reported.

According to analysts, Obama's Saturday night speech marked some of his harshest words yet about Republican presidential candidate Trump, as well as his most forceful call on the African-American community to support Democrat nominee Clinton.

Obama referred to the businessman as "somebody who has fought against civil rights and fought against equality and who has shown no regard for working people most of his life."

During his address, he also made fun of the so-called "birther" (if Obama was born in the US) controversy, saying "There's an extra spring in my step tonight. I don't know about you guys, but I am so relieved that the whole 'birther' thing is over."

"IS (Islamic State), North Korea, poverty, climate change -- none of those things weighed on my mind like the validity of my birth certificate," Obama added.

Speaking before the President, Clinton lauded Obama and also took on the birther controversy, CNN noted.

"Mr. President, not only do we know you are an American, you are a great American," Clinton, who served as Obama's secretary of state (2009-2013), added.