Police officials are reviewing whether to restrict access to a public park outside the courthouse where Donald Trump is on trial after a man set himself on fire there.

“We may have to shut this area down,” New York City Police Department Deputy Commissioner Kaz Daughtry said at a news conference outside the courthouse on Friday, adding that officials would discuss the security plan soon.

Collect Pond Park has been a gathering spot for protesters, journalists and gawkers throughout Trump’s trial, which began with jury selection on Monday.

Crowds there have been small and largely orderly, but at around 1.30pm on Friday a man took out pamphlets espousing conspiracy theories, threw them around, then doused himself in an accelerant and set himself on fire, officials and witnesses said.

A large number of police officers were nearby when it happened. Some officers and bystanders rushed to the man’s aid. He is in critical condition in hospital.

The man, who police said had travelled from Florida to New York in the last few days, had not breached any security checkpoints to get into the park.

Until Friday, the streets and pavements in the area around the courthouse were generally wide open, though the side street where Trump enters and leaves the building is off limits.

People accessing the floor of the large courthouse where the trial is taking place have to pass through a pair of metal detectors.

Authorities said they were also reviewing security outside the courthouse.

“We are very concerned. Of course we are going to review our security protocols,” NYPD Chief of Department Jeffrey Maddrey said.