A 16-week-old baby is undergoing a critical surgery in Brisbane, Australia after he was slashed in the face with a knife multiple times, allegedly by his grandmother.

The child sustained serious cuts to his face, Inspector Daniel Bragg told reporters at the Ridgeway Street, where the shocking incident took place on Tuesday (17 October), according to Australian Associated Press. He said that emergency services rushed the child to the hospital immediately.

Bragg added that the mother told them she visited the Ridgeway Street house the previous day with her baby and stayed the night. After around 6am in the morning, she heard her son crying and noticed the 64-year-old woman standing near the crib and a large knife was at the scene.

"The mother found the child in a distressed state with injuries to his face. She's clearly distraught over what's occurred. She's provided police with all the assistance she could," the officer added.

Police said the grandmother was assisting in the inquiry and they were yet to file any charges in the case.

"Clearly, when a young child has sustained such critical injuries, this isn't the work of a well-adjusted, happy individual," Bragg said of the suspect. He also said that paramedics who attended the crime scene were visibly shaken at the sight.

"It was distressing to see such injuries to such a small child. This is the worst-case scenario," he noted.