A homeless man attacked two children — a 16-year-old girl and her 9-year-old brother — with his fists and a piece of wood in a Brooklyn public housing project, police said.

“They were in the lobby waiting for a bus,” a police spokesman said Tuesday. “Then all of a sudden, he just attacks them.”

Charles Matthews hit both siblings in the head at about 7 a.m. at 869 Flushing Ave. in the Bushwick Houses, cops said.

The victims were hospitalized with minor injuries.

The suspect then attacked a 42-year-old woman in another building in the same housing complex minutes later, cops said. Her condition wasn’t immediately known.

Matthews, who was captured on video at the scene wearing a yellow shirt, ran off after the attack, but was caught by cops a few blocks away on Broadway near Park Avenue, authorities said. He was arrested on charges of assault, endangering the welfare of a child and criminal possession of a weapon.