New York, Sept 17 : Two young radicalised alleged assassins appeared in US courts in a nation focused on rising political violence.

Tyler Robinson, 22, appeared in a local Utah court remotely to face charges in the killing of Charlie Kirk, a close supporter of US President Donald Trump, last week.

He is charged with the murder of the Conservative youth activist, and the prosecutor said that he would seek the death penalty, which in the state can be carried out by a firing squad.

In New York, a local judge threw out terrorism charges against Luigi Mangione, 27, who is charged with killing a health insurance CEO last year, but retained murder charges against him.

New York State does not have the death penalty.

Mangione has emerged as a lightning rod for the fury of some people against health insurance companies, and his supporters rallied in front of the court in protesting his prosecution.

A fund for his legal defence has collected over $1 million in public contributions.

Mangione allegedly shot dead United Healthcare CEO Brian Thompson in the middle of New York City last December, and in a manifesto ranted against 'parasitical' health companies driven by profit motive.

Both men will also face charges in a federal court under federal statutes, which could carry the death penalty.

In the US, there are parallel federal and state justice systems, and the laws and penalties vary by state.

Prosecutors said that Robinson's mother recognised him from pictures circulated of the suspect in Kirk's killing, and informed his father, who confronted him and arranged his surrender.

They said that Robinson had admitted to the shooting in messages to his roommate, a man transitioning to woman.

Ironically, he said he had committed the assassination because "the guy spreads too much hate', according to officials.

Kirk's murder was the latest in an unsettling spate of violence with political or similar motives across the US, many of them by radicalised young people.

Twenty-year-old Thomas Matthew Crooks tried to assassinate US President Donald Trump when he was campaigning in Pennsylvania last year.

While Trump was injured, another man was killed, and Crooks was shot dead by a Secret Service agent.

Another assassination attempt, also last year by an older person, was thwarted in Florida and his trial began last week.

Robin Westman, a 23-year-old transgender female, killed two children and injured 18 others at a school-related event at a Minneapolis church before committing suicide last month.

Shane Tamura, 27, killed four people in July at a building in New York that houses the National Football League and committed suicide. He had said that he suffered brain injuries as a result of playing American football and seemed to blame the league for not doing enough to prevent the trauma.

In June, Vance Boelter, 57, allegedly killed former Minnesota House of Representatives Speaker Emerita Melissa Hortman and her husband.

Pennsylvania Governor Josh Shapiro escaped an assassination attempt by Cody Balmer, 38, who allegedly set fire to his official residence in April.

/IANS