Trump makes Joe Biden's son top campaign target

At a rally in Minnesota, US President Donald Trump targeted Hunter Biden, the son of the former Vice President and Democrat 2020 candidate Joe Biden, by ridiculing the 49-year-old as a loser, accusing him of profiting off his father's name and turning him into a campaign prop.

In his first campaign rally since the House Democrats formally began an impeachment probe against him, Trump on Thursday made it clear that Hunter Biden would be a top target as he unrolled his re-election bid, Efe news reported.

Trump said he wanted his campaign to print "Where's Hunter?" T-shirts.

"I want to see Hunter," Trump said, mocking the younger Biden as "not too smart".

"Hunter, you know nothing about energy," he went on. "You know nothing about China. You know nothing about anything, frankly."

The President also attacked Joe Biden, who is a leading Democratic presidential candidate and could face Trump in the 2020 election.

"He was only a good Vice President because he understood how to kiss Barack Obama's a**," Trump said.

The House Democrats' impeachment probe focuses in large part on Trump's dealings with Ukraine related to the Bidens.

Trump, on a phone call with his Ukrainian counterpart on July 25, pushed for an investigation into the Bidens and other matters.

Democrats called it a case of improperly using the power of the presidency to boost his own political fortunes. Trump has denied wrongdoing.

The White House wants Kiev to investigate energy company Burisma Group and Hunter Biden, who served on its board, and look into the actions of Joe Biden when he was overseeing US policy on Ukraine.

Trump has also asked China to look into Hunter Biden's work at a private-equity fund.

Joe Biden has rejected the president's allegations and defended his work fighting corruption in Ukraine. This week he joined the calls for Trump's impeachment.

At his rally Thursday night, Trump also sought to discredit the whistleblower who raised concerns about the July phone call, alleging he worked with Joe Biden.

"This is nothing but a partisan witch hunt," the President said.

During one moment of Thursday's 105-minute rally, Trump spoke affectionately of his own son, Eric Trump, who attended the event. Trump repeatedly referred to him as "my boy".

"They're our boy and they're our girls and it doesn't matter how old we get or how old they get," Trump said.

Eric Trump warmed up the crowd for his father, and took his own shots at Hunter Biden, which led to a "lock him up" chant from the crowd.

"We don't need to lock him up," said Eric Trump, who just moments earlier had suggested the cheer to the crowd. "We're just going to beat the hell out of him. We're going to win."

By the end of the rally, the Trump campaign website was selling black "Where's Hunter?" T-shirts.