The suspected gunman who tried to storm the White House correspondents’ dinner appeared in federal court and was charged with three federal crimes on Monday, including attempting to assassinate the president.

The alleged shooter, identified by law enforcement agencies as Cole Tomas Allen, a 31-year-old man from Torrance in southern California, was charged with attempting to assassinate the US president, transportation of firearms to commit a felony, and unlawful discharge of a firearm during violence.

The first charge carries a potential sentence of up to life in prison.

Court papers laying out the charges were not immediately available. Allen was being represented by lawyers with the federal defender’s office and sat beside them in court in a blue jail jumpsuit. Allen had three US marshals directly behind him during his appearance.

Allen has no record of criminal charges or a civil court history in Los Angeles county, according to a records search.

The weapons he had on him Saturday night included a 12 gauge pump action shotgun, a pistol and three knives, according to Jocelyn Ballantine, a federal prosecutor.

Judge Matthew Sharbaugh asked Allen if he had taken any drugs in the last day or so, to which Allen responded no.

In an unusual appearance, Jeanine Pirro, the US attorney for the District of Columbia, was also present in the courtroom, seated in the front row. After the initial appearance at court, Pirro joined acting attorney general Todd Blanche and FBI director Kash Patel at the Department of Justice for a press conference to discuss the charges.

Pirro said that while there were only three charges on the file now, “there will be additional charges” as the case unfolds.

“Let this be a message to anyone who thinks that Washington DC is the place to act out political violence,” Pirro said. “And if you are willing to do so with a firearm and cross state lines, we will find you, we will track your steps from the inception of your plans and we will prosecute you to the fullest extent of the law.”

Blanche said Allen arrived at the Washington Hilton on Friday, 24 April, and the following evening, at 8.40pm, rushed through security one floor above the reception before he was apprehended. Blanche said one officer was shot in the chest but was wearing a ballistic vest, and that officer fired five times but the attacker was not hit.

Allen will return for a detention hearing on 30 April and a preliminary hearing on 11 May .

On Sunday, Blanche had said that the alleged gunman who had charged towards the ballroom where the black-tie event was being held on Saturday night but was stopped, was believed to have been targeting top officials of the Trump administration who were at the dinner, “likely including the president”.

He was also “not actively cooperating” with the authorities, Blanche added.

Investigators have yet to establish a motive. They believe that the suspect was armed with a shotgun, a handgun and multiple knives when he was arrested, and that he acted alone. Police have been searching an address in Torrance linked to Allen, and writings reportedly found in his hotel room are also being examined as part of the investigation.

The suspect is thought to have traveled by train from California to Chicago and then on to Washington, where he checked in as a guest at the Washington Hilton hotel, where the glitzy annual journalists’ gala was being held.

Trump and his officials were rushed to safety after the alleged gunman charged through a security checkpoint outside the hotel ballroom and shots were fired before he was subdued by law enforcement officers. A federal agent was shot but was wearing a bulletproof vest, and was discharged from the hospital on Sunday.

Trump had agreed to attend this year’s dinner for the first time as a sitting president after boycotting previous years. Several top members of his cabinet, including Vice-President JD Vance, Defense Secretary Pete Hegseth and Secretary of State Marco Rubio were also in attendance, along with thousands of members of the media.

Trump called the attacker a “lone wolf whack job” as he returned to the White House on Saturday night in an extraordinary news conference soon after the incident, with the president and several members of the press still in their ballroom attire.

After leaving the same hotel where former president Ronald Reagan was shot in 1981, Trump told reporters that being president was “a dangerous profession”. “When you’re impactful, they go after you. When you’re not impactful, they leave you alone,” he said.

“It’s always shocking when something like this happens,” Trump went on. “I can’t be so concerned that I can’t function.”

Despite police still working to establish a motive, White House press secretary Karoline Leavitt claimed on Sunday morning that the event was “hijacked by a depraved crazy person who sought to assassinate the president and kill as many top Trump administration officials as possible”.

The Associated Press contributed reporting