Inside the courtroom as Donald Trump heard the charges against him

Shortly after 14:30E, a former president of the United States walked into a Manhattan courtroom as a defendant.

Donald Trump entered surrounded by his Secret Service detail, wearing his signature blue suit and red tie, and an electric buzz shot through the room.

His expression was sombre and his steps seemed heavy and slow as he walked down the courtroom's centre aisle to take his place at the front, where his defence attorneys waited for him.

Mr Trump never addressed the press, and gave little away through expressions or body language.

I sat five rows directly behind the former president, in a group of journalists watched over by more than a dozen police officers. We were banned from using our phones or laptops in court.

When the judge, Juan Merchan, arrived, everyone rose for him, including Mr Trump. Despite the media and political circus happening 15 stories below the courtroom, Judge Merchan presided in an even tone, never raising his voice.

The hearing mostly dealt with procedural matters, including deadlines for the lawyers and the next court date, but the weight of its significance was lost on no-one in the room.

Though Mr Trump is known for his political pageantry, he spoke only briefly.

When the judge read the 34 felony counts brought against him, he replied: "Not guilty."

Then at one point, Judge Merchan addressed Mr Trump directly, reminding him that he had a right to be present at all proceedings related to his case. Asked if he understood this, Mr Trump replied: "Yes."

The judge then added that if Mr Trump, like any defendant, behaved in an unruly or disruptive manner, he might lose the right to be present at his trial.

As they made their arguments, prosecutors mentioned that Mr Trump had made threatening posts on social media, including one that warned of potential "death and destruction" if he was charged.

Mr Trump's lawyers said their client was frustrated and upset with the case, which he believed to represent a "great injustice".

The judge responded by telling the defence attorneys: "I don't share your view that certain rhetoric and certain language is justified by frustration."

Judge Merchan said his warning about further inflammatory rhetoric was a request and not an order, but he would have to take "a closer look" if the issue arose again.

The judge brought proceedings to a close after nearly an hour.

Mr Trump stood, and was immediately surrounded by his Secret Service detail. The former president spoke quietly to his lawyers, but he was inaudible to the press sitting a few rows behind him.

Then he turned and walked down the centre aisle of the courtroom, out the rear door he had first entered. He said nothing to the pack of television cameras outside. His expression was quite serious.

The first criminal case involving a US president was under way.