A 21-year-old Northeast man was shot and two students were injured yesterday in a lunchtime brawl on the parking lot of McKinley High School, Second and T streets NE, police reported.

The melee, which resulted in four arrests, began shortly before 1 p.m. when a fistfight broke out among students during recess. Michael Green, 19, and his brother, Steven, 21, of 111 Rhode Island Ave. NE, left the fight and returned with a shotgun, according to police.

Police said two shots were fired. Craig Riddick, 20, of 907 Jackson St. NE, was wounded in the back, arm and ear, according to a spokesman at the Washington Hospital Center, where he was reported in serious condition after surgery.

Michael and Steven Green were charged with assault with intent to kill while armed. Neither Steven Green nor Riddick is a student at McKinley, police said. Michael Green is enrolled there.

"It was total chaos in here; half the school didn't even come back to class" after the shooting, one student said.

The Green brothers were arrested by two police officers who saw them running from the school after the 1:35 p.m. shooting. Also arrested at the home was Tujana Green, 22, their sister, who was charged with disorderly conduct and possession of marijuana, police said. A cousin, Denu Patricia Hilliard, 20, was charged with disorderly conduct, officers said.

The two students injured in the fight were identified as Wayne Martin, 19, of 146 U St. NE, and Rodney Williams, 15, of 2033 Second St. NE. Martin, who police said was struck in the head with a hammer, suffered severe lacerations. Williams suffered an abdominal injury.