A 15-year-old girl accused of knocking a classmate's front teeth out in an "unprovoked attack" at a McDonald's store in suburban Adelaide has been denied bail.

Key points: The court heard the alleged attack was in response to a racist Instagram comment

The court heard the alleged attack was in response to a racist Instagram comment The accused girl has no criminal history

The accused girl has no criminal history The court was told she laughed during her interview with police

The Adelaide Youth Court heard the 13-year-old victim was hit multiple times in the fast food outlet on Tuesday and has since undergone surgery for her injuries.

WARNING: This story contains an image that some people may find distressing.

Police prosecutors told the court her alleged attacker — who cannot be identified for legal reasons — made full admissions in a police interview and laughed about the allegations.

The 15-year-old was one of two teenage girls charged with aggravated assault over the incident.

A 14-year-old co-accused was bailed to appear in court in March, but has since been re-arrested and charged with breaching bail over alleged threats made on social media.

Footage of the attack was also shared on social media and the court heard the alleged assault was in response to a racist comment posted on Instagram.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 12 seconds 12 s Video of the incident was posted online.

The Magistrate has ordered a bail report.

"It appears to be an unprovoked attack on the victim," the prosecutor told the court.

"The defendant says that it was in response to a racist comment which was put on Instagram.

The accused girl made 'full admissions'

"The defendant has then proceeded to strike the victim … numerous times which has caused a number of her teeth to be pushed out.

"She did make full admissions.

"And quite concerningly, at some point throughout the record of interview and discussing this information with police, she laughed about the allegations."

The student had her teeth knocked out. ( Supplied: Victim's family )

The court heard she has no criminal history.

Outside court, the girl's father said he was sorry for the injuries inflicted on the victim.

The matter will return to court next week.

Education Minister John Gardner said it was an "absolutely appalling incident".

"I think it's of great concern to our entire community whenever you see distressing footage of this nature," he said.

"Without wanting to make any comments that would jeopardise the police investigation or any further action that would be taken in court … it's a phone call no [parent] ever wants to receive.

"All of our hearts go out to the victim of this, and indeed any other incident like this."

He said the Education Department was supporting students at the school.