BOSTON - Lawyers for the accused Boston Marathon bomber filed on Thursday a last-gasp request to dismiss the charges against their client or delay the start of the trial next week, contending that court officials had violated their own rules during jury selection.

Attorneys for Dzhokhar Tsarnaev, who is accused of carrying out the largest mass-casualty attack on US soil since Sept. 11, 2001, argued in a court filing that after randomly assigning numbers to the more than 1,350 people who reported for initial selection early last month, the court re-ordered the jurors based on arrival time.

That, they contended, resulted in fewer potential black jurors being screened during the past two months of in-person questioning that wrapped up on Wednesday. They also contend that people who live within the Boston city limits and those under 30 and over 70 were disproportionately under-represented.

The final phase of jury selection is set to take place on Tuesday, when prosecutors and defense attorneys will whittle down the field of about 70 provisionally qualified jurors to 18 people, including 12 jurors and six alternates.

Tsarnaev faces the possibility of the death penalty if he is convicted of killing three people and injuring 264 in the April 15, 2013, bombing.