Seven more teenagers were arrested on Friday for their roles in the stabbing death of a Nassau County high school student earlier this month, authorities said.

The suspects — 19-year-old Haakim Mechan; 18-year-old Marquis Stephens; 18-year-old Javonte Neals; 17-year-old Taj Woodruff; 17-year-old Sean Merritt and two younger teens who were not named — were all hit with gang assault charges in the slaying.

Police Commissioner Patrick Ryder will formally announce the arrests related to the fatal stabbing of 16-year-old Khaseen Morris at a press conference Saturday morning, authorities said.

Morris was knifed once in the chest near a strip mall by his high school after being attacked by a group of teens in an apparent beef over a girl on Sept. 16, police said.

Morris knew the ex-boyfriend of a girl he had walked home from a party earlier in the week was trying to confront him, police said.

As he suffered from the stab wound, teens recorded him with their cellphones instead of offering help, police said at the time.

“Kids stood there and didn’t help Khaseen,” Detective Lt. Stephen Fitzpatrick told reporters, Newsday reported. “They’d rather video. They videoed his death instead of helping him.”

Two days after the attack, police arrested Tyler Flach, 18, of Lido Beach and charged him with murder, authorities said.

After the slaying, police said they were searching for six to seven other teens in the attack after interviewing witnesses and reviewing footage posted on social media, including on Snapchat.