The son of Hillary Clinton's running-mate Tim Kaine has been arrested after a protest against a pro-Trump march turned violent.

Linwood Michael Kaine, 24, was arrested at the weekend by police in the city of St Paul, Minnesota.

He was detained for three days and released yesterday, according to Pioneer Press, a Minnesota newspaper.

The city's lawyer is considering filing misdemeanour charges, the Pioneer Press reported.

Advertisement

Four other people at the rally were arrested on suspicion of second-degree riot, and another was brought in for disorderly conduct. They, too, were released without charges.

Pro-Trump rallies were held across the country on Sunday, with mostly-peaceful crowds gathering to express their support for the President.

But in Minnesota, a crowd of around 50 people confronted the 400 pro-Trump marchers, who had gathered at the state capitol to hear speeches. Fireworks were lit, smoke bombs were set off and a chemical irritant was sprayed into the crowd.

Steve Linders, a police spokesman, told the Pioneer Press that Kaine ran from the scene and was arrested down the street from the building, with four others suspected to have lit fireworks.

Kaine resisted the arresting officer, who had to use "some force" to take him into custody, Linders said.

"He turned around and squared up to fight with the officer," said Linders.

"The officer was able to place Mr Kaine under arrest and take him to the Ramsey County jail for booking."

Police told the Pioneer Press they did not know until yesterday that they had arrested a US senator's son. No one from the senator's office contacted the department about it, they said.

Kaine, who goes by the nickname Woody, attended a small liberal arts college about 45 minutes south of St Paul and is a resident of Minneapolis.

Tim Kaine and his wife, Anne Holton, gave a brief emailed statement to the Washington Post through a spokeswoman.

"We love that our three children have their own views and concerns about current political issues," they said.

"They fully understand the responsibility to express those concerns peacefully."

Their oldest son, Nat, is a US Marine who has deployed overseas. Their daughter, Annella, is a college student.