BOSTON — Attorneys for the accused Boston Marathon bomber on Thursday asked a U.S. appellate panel to override a federal judge and order his trial moved out of the city, saying an impartial jury could not be seated so close to the site of the 2013 attack.

U.S. District Judge George O’Toole has three times rejected pleas by Dzhokhar Tsarnaev’s lawyers to move the trial out of the city where the bombing killed three people and injured 264.

“This attack was viewed as an attack on the marathon itself … and an attack on the city of Boston,” attorney Judith Mizner, representing Tsarnaev, 21, told the three-judge panel.

Thousands of Boston-area residents were crowded around the race’s finish line when twin bombs went off on April 15, 2013, and hundreds of thousands were ordered to remain in their homes four days later while police conducted a massive manhunt for Tsarnaev.

That degree of personal connection to the incident will make it very difficult to empanel an impartial jury in Boston, said Mizner, adding that would be less of a problem in other major cities.

“You aren’t going to have people in Washington who say, ‘My best friend was standing by the finish line,’” Mizner said.

Assistant U.S. attorney William Weinreb noted that jury selection, which began early last month, has already identified 61 people who could serve on the jury through the in-person questioning process known as “voir dire.”

“The voir dire process is working,” Weinreb said.

It has also turned up some potential candidates with strongly held presumptions on Tsarnaev’s guilt, said Appellate Judge Juan Torruella.

He noted that several of the more than 1,350 potential jurors stated on their questionnaires that there was no sense in having a trial as they believed Tsarnaev was guilty. Others went even further.

“With this case, I think a public execution would be appropriate, preferably by a bomb at the finish line of the Boston Marathon,” Torruella read from a questionnaire.

Weinreb countered that sort of statement was not typical of potential jurors’ responses and made it easy to identify those who were unable to keep an open mind and thus unfit to serve on the jury.

“People who have strong feelings about this case are unhesitatingly admitting them,” he said.

The appellate panel did not make an immediate decision on the request.

Tsarnaev could face the death penalty if convicted, a fact that has also complicated jury selection. Massachusetts state law does not allow for capital punishment and many of the more than 200 candidates who have been questioned in recent weeks have said they would have a hard time voting to execute someone.

Tsarnaev is also accused of fatally shooting a police officer three days after the bombing as he and his older brother, Tamerlan, prepared to flee the city. Tamerlan Tsarnaev, 26, died that night following a gun battle with police.

As an example of how pervasive the memory of the bombing is through the city, Mizner noted that on several of the active construction sites that surround the waterfront courthouse, cement trucks are painted with the words “Boston Strong,” a slogan that became the city’s rallying cry after the attack.