Jury selection began Monday in the trial of Donald Trump in New York City — the first criminal trial of a former president in US history — on allegations that he falsified documents to cover up a sex scandal involving an adult film actress.

Jury selection could take up to two weeks, with the entire trial expected to last between six and eight weeks.

The first set of prospective jurors, consisting of 96 New Yorkers from Manhattan, entered the courtroom in the afternoon.

Judge Juan Merchan welcomed them and introduced the defense team. All stood, including Trump, who gave the prospective jurors a tight smile, according to pool news reports.

As the judge read instructions to the potential jurors, Trump sat back in his chair with his arms folded across his body. He occasionally looked up, and when Merchan said it will be his responsibility to impose an appropriate sentence, Trump chuckled, according to the pool report. He chuckled again when Merchan said he will ensure a fair trial.

Of the 96 possible jurors, more than 50 raised their hands to say they couldn't be fair. They were immediately excused.

At least nine more prospective jurors were excused after raising their hand when Merchan asked if they couldn't serve for any other reason. Those reasons were not disclosed.

That leaves approximately 34 jurors out of the 96 who entered court in the initial panel.

Merchan also can dismiss jurors for other reasons, such as financial hardship or a fear of serving in a high-profile case. Additionally, the prosecution and defense can each scratch up to 10 jurors from the pool for any reason.

Trump's lawyers and the prosecutors will seek to whittle the group of potential jurors down to 12, plus six alternates.

Merchan adjourned court for the day after nine potential jurors had gone through a lengthy questionnaire.

Before making his way inside the courtroom Monday morning, the presumptive Republican nominee for president addressed reporters outside.

"This is really an attack on a political opponent. That's all it is," Trump said. "So I'm very honored to be here."

Trump is accused of 34 counts of falsifying business records in connection with a hush-money payment his former lawyer and fixer, Michael Cohen, made to adult-film actress Stephanie Clifford, also known as Stormy Daniels, to cover up an alleged affair ahead of the 2016 election. Trump has pleaded not guilty.

Trump, who might take the witness stand in his own defense, has denied the sexual encounter with Daniels. But prosecutors say that, while serving as president, he allowed his company to falsify records to hide the reimbursements to Cohen.

They argue the payment to Daniels was part of a pattern: Trump, faced with damaging stories that could have doomed his campaign, concealed them to influence the election.

After Merchan called the proceedings to order just before 10 am, he quickly denied a second motion from Trump's legal team asking him to recuse himself from the case. Trump's attorneys had argued that Merchan should step aside because of his daughter's employment at a consultancy firm that does work for Democratic candidates and progressive groups.

Merchan said their argument relied upon "a series of inferences, innuendos and unsupported allegations''.

Trump's lawyers and prosecutors from Manhattan District Attorney Alvin Bragg's office argued over a handful of outstanding issues related to evidence, rules for the trial and what questions potential jurors should be asked. The judge sided with both the prosecution and the defense in a series of pretrial rulings.

The judge also said prosecutors couldn't play for the jury the 2005 Access Hollywood recording in which Trump was captured discussing grabbing women sexually without their permission. However, prosecutors will be allowed to question witnesses about the recording, which became public in the final weeks of the 2016 campaign.

Merchan briefly addressed prosecutors' arguments about whether Trump has broken his gag order that barred him from publicly commenting on witnesses in the case. The judge said he will hear arguments on April 24 and then changed the date to April 23 at 9:30 am ET.