NEW YORK — Sen Bob Menendez, a Democrat, went on trial in Manhattan federal court Monday, accused of accepting bribes of gold and cash to use his influence to deliver favors that would help three New Jersey businessmen.

Menendez, 70, sat with his lawyers and listened as Judge Sidney H. Stein told two separate groups of 50 prospective jurors about the charges against Menendez and two of the businessmen.

The judge told them the “sitting U.S. senator from the state of New Jersey” had been charged in a conspiracy in which he allegedly “agreed to accept bribes and accepted bribes.”

Sen. Bob Menendez, D-N.J., leaves the Manhattan federal court Monday, after the first day of his corruption trial. Stefan Jeremiah/Associated Press

After he warned them that the trial was expected to last up to seven weeks, Stein let jurors raise their hands if they believed they could not serve for that length of time. Then, he took them one at a time into a separate room to ask them why.

Menendez is on trial with two of the businessmen who allegedly paid him bribes – real estate developer Fred Daibes and Wael Hana. All three have pleaded not guilty. A third businessman has pleaded guilty and agreed to testify against the other defendants. The senator’s wife is also charged, but her trial is delayed until at least July.

Stein had not finished questioning prospective jurors who said they could not serve when he finished for the day without yet beginning the process of asking general questions of all jurors, such as whether they know any of the parties to the case, including lawyers, the defendants and possible witnesses.

The judge gave no indication whether he thought it was likely that openings would occur Tuesday.

When Menendez left the courthouse at the end of the day, he gave a friendly wave toward reporters who asked him to speak as he walked quickly to a waiting car, but he left any meaningful comment for another day.

In the morning, Menendez, in a suit with a red tie, was dropped off in front of the courthouse at 8:15 a.m., forty minutes before former President Donald Trump’s motorcade passed by on its way across the street to state court, where he is on trial for allegedly falsifying business records to hide hush money payments to a porn actor before the 2016 election.

Menendez did not speak to reporters who were kept behind barricades as he entered a security pavilion where everyone entering the courthouse is scanned.

The trial, the second in seven years for Menendez, has already sent the senator’s political stature tumbling. After charges were announced in September, he was forced out of his powerful post as chairman of the Senate Foreign Relations Committee.

The three-term senator has announced he will not be seeking reelection on the Democratic ticket this fall, although he has not ruled out running as an independent.

The previous corruption prosecution of Menendez on unrelated charges ended with a deadlocked jury in 2017.

In the new case, prosecutors say the senator’s efforts on behalf of the businessmen led him to take actions benefitting the governments of Egypt and Qatar. Menendez has vigorously denied doing anything unusual in his dealings with foreign officials.

Besides charges including bribery, extortion, fraud and obstruction of justice, Menendez also is charged with acting as a foreign agent of Egypt.

Among evidence his lawyers will have to explain are gold bars worth over $100,000 and more than $486,000 in cash found in a raid two years ago on his New Jersey home, including money stuffed in the pockets of clothing in closets.

The Democrat’s wife, Nadine Menendez, was also charged in the case, but her trial has been postponed for health reasons. She is still expected to be a major figure. Prosecutors say Nadine Menendez often served as a conduit between the men paying the bribes and Menendez.

The senator’s lawyers in court papers have said they plan to explain that Menendez had no knowledge of some of what occurred because she kept him in the dark.

According to an indictment, Daibes delivered gold bars and cash to Menendez and his wife to get the senator’s help with a multimillion-dollar deal with a Qatari investment fund, prompting Menendez to act in ways favorable to Qatar’s government.

The indictment also said Menendez did things benefitting Egyptian officials in exchange for bribes from Hana as the businessman secured a valuable deal with the Egyptian government to certify that imported meat met Islamic dietary requirements.

In pleading guilty several weeks ago, businessman Jose Uribe admitted buying Menendez’s wife a Mercedes-Benz to get the senator’s help to influence criminal investigations involving his business associates.