BOSTON -- A federal court official says Boston Marathon bombing suspect Dzhokhar Tsarnaev's trial will not begin as scheduled on Monday because jury selection is taking longer than anticipated.

Ginny Hurley, of U.S. District Court in Boston, said in an email Thursday that the process of selecting a jury is progressing "but in the interest of thoroughness is taking longer than originally anticipated."

The statement says the anticipated start date of Jan. 26 is "unrealistic." No new date has been set.

Tsarnaev is charged with 30 federal counts in the April 15, 2013, bombings that killed three people died and injured more than 260. Tsarnaev could face the death penalty if convicted. He has pleaded not guilty.

More than 1,350 people have filled out juror questionnaires.