Two people have been killed and five others injured in a shooting that took place during a high school graduation ceremony in Richmond, Virginia.

The shooting outside the Atria Theater sent students in graduation gowns running for safety, US media reports.

School officials say the shooting took place during a ceremony for the Huguenot High School.

Another graduation scheduled for Tuesday has been postponed and all classes are cancelled on Wednesday.

The victims who were killed an 18-year-old man who was part of the graduating class and his 36-year-old father, police say. Police have not yet released their identities.

A 19-year-old suspect has been taken into custody, according to Interim Richmond Police Chief Rick Edwards. He said that police believe that he knew at least one of the victims.

Another person was found armed with a handgun and was initially detained, but police now believe he was not involved in the attack.

The shooting took place in Monroe Park after the ceremony had ended at the Virginia Commonwealth University campus.

"Is nothing sacred any longer?" Richmond Mayor Levar Stoney asked at a news conference.

"A child should be able to go their graduation and walk at their graduation and enjoy the accomplishment with their friends and families," he said, calling the shooting a "selfish act".

In an alert sent to students on Tuesday, the university said that police were on the scene to respond to the shooting.

"There is no ongoing threat to the community but there is a heavy police presence at Monroe Park," the alert said.

Chief Edwards added that three off-duty officers were working inside the theater and seven more were stationed outside to direct traffic when the shots broke out.

At 17:13 local time (22:13GMT), police in the building reported hearing shots outside, he said.

As well as five injured by gunfire, who sustained non-life-threatening injuries, two people suffered falls and a nine-year old girl "was hit by a car during the melee", he continued.

Superintendent of Richmond Public Schools Jason Kamras said the attack occurred on what "is supposed to be a joyous day when our kids walk the stage and get their diploma".

"I don't have any more words on this I'm tired of seeing people get shot, our kids get shot and I beg of the entire community to stop," he continued.