Thousands of supporters of US President Donald Trump, including racist group Proud Boys, clashed with anti-Trump demonstrators in across the US.

Rallies backing President Donald Trump’s baseless claims of election fraud led to clashes in major US cities on Saturday.

Scuffles broke out in many places between rally-goers, including racist group Proud Boys, and counter-protesters who turned up to criticise the president, who lost the November 3 election to Democrat Joe Biden, but is yet to concede.

Washington State Police said in a tweet late Saturday that a shooting had taken place after clashes near the capitol building in Olympia, and that a suspect had been detained.

In the US capital, DC Fire and EMS Department communications chief Doug Buchanan told AFP that four people had been stabbed and were now hospitalised “with serious injuries.”

More than a 100 riot police were deployed to stop clashes.

According to authorities, four arrests were made and four officers were injured during the demonstrations.