Washington, Aug 20 (IANS): Former US President Barack Obama has warned that the country's democracy was at stake, adding that incumbent President Donald Trump was "categorically unfit" for the job, it was reported.

Obama's remarks were part of the ongoing Democratic National Convention (DNC), which he made virtually from the Museum of the American Revolution in Philadelphia on Wednesday, reports The Hill news website.

While urging voters to back his Vice President Joe Biden, the Democratic presidential candidate, Obama said: "I am also asking you to believe in your own ability – to embrace your own responsibility as citizens – to make sure that the basic tenets of our democracy endure.

"Because that's what's at stake right now. Our democracy."

He also warned against complacency, arguing that cynicism and apathy in the face of Trump's attacks on democratic norms would cause the entire system to wither away "until there's no democracy at all".

"This administration has shown it will tear our democracy down if that's what it takes to win," the former President was quoted as saying by The Hill news website.

In his address, Obama also slammed Trump over his character, treatment of protesters, attacks on the media and his lack of commitment to the job.

"I did hope, for the sake of our country, that Donald Trump might show some interest in taking the job seriously; that he might come to feel the weight of the office and discover some reverence for the democracy that had been placed in his care.

"But he never did... For close to four years now, he's shown no interest in putting in the work; no interest in finding common ground; no interest in using the awesome power of his office to help anyone but himself and his friends; no interest in treating the presidency as anything but one more reality show that he can use to get the attention he craves," he said.

Obama's affection for Biden, who he referred to as "a brother" was notable in the address.

"Joe and I came from different places and different generations. But what I quickly came to admire about him is his resilience, born of too much struggle; his empathy, born of too much grief."

Obama's speech came two days after his wife and former First Lady, Michelle Obama tore into Trump in an 18-minute speech on the inaugural day of the DNC.

Michelle Obama said that Trump is the "wrong president for our country".

"He has had more than enough time to prove that he can do the job but he is clearly over his head. He cannot meet this moment. He simply cannot be who we need him to be for us."