Cheering for Kamala Harris and urging his supporters to vote for her, former US President Barack Obama on Tuesday also slammed Republican nominee Donald Trump and said he will never lose his sleep thinking about the plight of Americans.

Addressing the National Democratic Convention, Obama targeted Trump, who is running for his second term to the White House, and said: "He killed a bipartisan immigration deal that would've helped secure our southern border because he thought trying to actually solve the problem would hurt his campaign."

He said Trump will never lose his night's sleep thinking about the plight of Americans.

Backing Kamala Harris for the top job, Obama, who served the US for two terms as President, said: "America is ready for a new chapter. America's ready for a better story. We are ready for a President Kamala Harris. And Kamala Harris ready for the job."

Echoing his 2008 campaign slogan 'Yes, we can' slogan, Obama chanted 'Yes, she can', voicing his support for Kamala Harris who will be fighting against Donald Trump in the way to become the next President of the country.

Praising President Joe Biden, who resigned from the presidential race earlier and nominated Kamala Harris to be the Democratic nominee, Barack Obama said: "History will remember Joe Biden as a president who defended democracy at a moment of great danger."

Obama said the entire world is closely watching the Presidential poll.

He said the US cannot be the 'world's policemen' but a 'force for good'.