Nikolas Cruz, the man charged with killing 17 people at a high school in Parkland, Fla., in February, faces three new charges of assaulting an officer in jail and grabbing his electroshock weapon, the authorities said on Wednesday.

Mr. Cruz, 20, is being held in the Broward Sheriff’s Office’s main jail, in Fort Lauderdale, Fla., as he awaits trial on 34 counts of premeditated murder and attempted murder in the shooting on Feb. 14 at Marjory Stoneman Douglas High School.

The new charges relate to a fight with a deputy at the jail on Tuesday, shortly before 6 p.m., the sheriff’s office said in a statement on Wednesday. The deputy, Sgt. Raymond Beltran, told Mr. Cruz to “not drag his sandals on the ground” in a day room, according to an affidavit. It said Mr. Cruz made an obscene gesture at the sergeant and “rushed” him and “struck him in the face.”

The two men ended up on the ground, the affidavit said. Video, which the authorities did not release, shows that Mr. Cruz was on top of Sergeant Beltran at one point, punching him multiple times in the head, according to the affidavit.