MINNEAPOLIS (AP) -- President Donald Trump is lashing out at potential Democratic presidential rival Joe Biden and his son Hunter.

Trump says at a rally Thursday in Minneapolis that Biden became Barack Obama's vice president because he knew how to curry favor with Obama.

The Republican president is also targeting Hunter Biden, suggesting a T-shirt that says ``Where's Hunter?''

Trump has been spreading groundless claims that the Bidens used their family name to get China and Ukraine to pay them millions of dollars.

The Democratic-controlled House opened an impeachment inquiry after a whistleblower complained about Trump's dealings with Ukraine and alleged Trump was abusing his public office for personal political gain. Trump later released a rough transcript of a phone conversation with Ukraine's president in which he asks for an investigation of Biden.