The California man who allegedly tried to assassinate President Donald Trump at a Washington gala has been indicted on a fourth charge of assaulting a US officer or employee with a deadly weapon.

The new charge comes in the wake of questions over whether a Secret Service officer - who was shot but not seriously wounded in the attack at the White House Correspondents Dinner on 25 April - was hit by crossfire from another officer.

US Attorney Jeanine Pirro signed off on the new indictment unsealed on Tuesday, which supersedes the previous charges.

Cole Tomas Allen, 31, appeared in court in Washington DC last week. He has not yet entered a plea.

According to court documents filed on Tuesday, a grand jury also indicted Allen on charges of attempting to assassinate the US president as well as two firearms offences - transportation of a firearm and ammunition in interstate commerce with intent to commit a felony, and using, carrying, brandishing and discharging a firearm during a crime.

Allen was previously charged on those counts last week via criminal complaint.

The suspect was carrying a semi-automatic handgun, a pump-action shotgun and three knives as he allegedly rushed through a security checkpoint one floor above the basement venue at the Washington Hilton hotel on 25 April, prosecutors have said.

After gunfire rang out, Trump, Vice-President JD Vance, cabinet members and other White House officials were rushed from the hotel ballroom as dinner attendees sheltered under tables.

The incident has sparked a White House security review.

The Torrance, California, man studied at the prestigious California Institute of Technology, and worshipped at the Pasadena United Reformed Church in the Los Angeles area.

Federal campaign finance records show he donated $25 to a Democratic Party political action committee in support of Kamala Harris for president in 2024.

He allegedly sent an email to his family shortly before the attack that said, "Administration officials... are targets, prioritised from highest-ranking to lowest", according to court records.

"I would still go through most everyone here to get to the targets if it were absolutely necessary," he allegedly added.

Allen, who remains in custody, could face life in prison if found guilty. (BBC)