Donald Trump's vice president Mike Pence took centre stage on the third night of the Republican national convention to warn voters they "won't be safe in Joe Biden's America" - and cast Mr Trump as their protector against the "radical left."

Mr Pence was the keynote speaker in a parade of Trump acolytes who sought to uplift the president as a champion of US values and civil rights.

They also spoke of dark forces intent on ending the American dream and said losing to their Democratic rivals is not an option.

Mr Pence made the case for Mr Trump getting a second term instead of allowing the nation to be "fundamentally transformed" by a Biden administration they say would take an uncharted path towards socialism and mob rule.

"The hard truth is... you won't be safe in Joe Biden's America," the 61-year-old said.

Touting Mr Trump's strong record on the economy before the Covid-19 pandemic struck, and his ongoing efforts to revive it, Mr Pence urged voters to ask themselves "who do you trust to rebuild this economy?"

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"A career politician who presided over the slowest economic recovery since the Great Depression? Or a proven leader who created the greatest economy in the world?"

Mr Pence's address came amid a new flare-up of racial tensions in the United States, with protests spreading over the latest police shooting of an African-American man, Jacob Blake, who was shot in the back seven times by police in Kenosha, Wisconsin.

Mr Trump has announced he is sending in additional federal forces to quell unrest in the Midwestern city, where two people were shot dead during anti-police protests on Tuesday.

A 17-year-old boy has been arrested on murder charges over the deaths.

Addressing the latest unrest, Mr Pence struck a tough tone.

"Let me be clear," he said. "The violence must stop whether in Minneapolis, Portland or Kenosha," he said.

"We will have law and order on the streets of this country for every American of every race and creed and colour."

A former congressman and governor of the Midwestern state of Indiana, Mr Pence has taken on the role of calm counterweight to  MrTrump's constant drama, one who is impeccably conservative and manifestly religious.

Mr Pence is playing an important part in Mr Trump's reelection, crisscrossing the country - with an emphasis on swing states such as Wisconsin - to drum up support.

He has similarly served as the White House's sober pointman on the coronavirus pandemic, which has killed nearly 180,000 Americans since Mr Trump's initial, erroneous prediction that it would disappear without trouble.

Where Mr Trump has veered radically between dismissing the crisis and grimly embracing a self-declared role as a "wartime president," Mr Pence has shouldered the unglamorous role of White House coronavirus task force coordinator.

Polls show almost two-thirds of Americans are unhappy with Mr Trump's performance during the pandemic.

Mr Pence's opponent in the race, Democratic vice presidential pick Kamala Harris, will be attacking Mr Trump on his coronavirus record at a speech later today in Washington, the same day Mr Trump gives his main acceptance speech of the Republican convention at the White House.