(CNN) -- It started with older youths boarding an Australian school bus, terrifying the elementary-school-aged Jewish children aboard with slurs from "Heil Hitler" to "kill the Jews," and it ended 40 minutes later when the older youths fled before police arrived, according to accounts from some of the young students on the bus.
"When they saw us all in tears, they were laughing," 12-year-old student Noa Stanton told CNN affiliate 7 News in Australia, referring to the older youths who stayed on the bus as it traveled in the suburbs of Sydney.
The youths fled following the Wednesday incident, Sydney police said, but five suspects were arrested Thursday and authorities were waiting on a sixth to turn himself in. No charges were immediately filed and the youths -- described by police as intoxicated -- were released to their parents.
The two dozen children, aged 5 to 12, were heading home from three Jewish schools when the older boys made their way onto the bus and began spouting threats of violence and anti-Semitic slurs, police and the Jewish students said.
Noa Stanton said the boys told her and her frightened classmates they had been "popping drugs in the city" -- even offering the children drugs, she said.
Noa's 8-year-old sister, Anais, told 7 News she also witnessed the boys holding bottles of alcohol.
Several children on the bus called their parents on cell phones. Isabel Stanton said when she answered a call from one of her daughters, "I couldn't understand a word she was saying. She was hysterical and crying on the phone."
Another mother, Jacqui Blackburn, told 7 News she received a similarly chilling call from her three daughters on the bus. Her terrified girls told her drunk men had boarded the bus and were yelling, "Heil Hitler" and "kill the Jews," and threatening to cut the throats of those on board.
The students from Mt. Sinai College, Emmanuel School and Moriah College said they endured verbal abuse from Maroubra to Bondi Junction, east of Sydney, where the teens eventually fled before police, called by parents, arrived. It was unclear Thursday whether the driver of the school bus made any effort to alert authorities or took any other action during the incident.
Waverly Police Department Superintendent Jason Box confirmed to CNN affiliate Sky News that "six juvenile males boarded the bus ... and made offensive and threatening comments towards approximately 25 schoolchildren." The youths apparently used student bus passes to get on board and some of them were wearing school uniforms, Box said.
According to Sky News, the teens are believed to be between the ages of 15 and 17.
Box called the incident opportunistic, "isolated and random."
The president of the New South Wales Jewish Board of Deputies, Vic Alhadeff, called the incident "sickening."
"Any racist incident is unacceptable in our society. It is particularly sickening when those being targeted are young children," Alhadeff told 7 News.
New South Wales Communities Minister Victor Dominello said Jewish leaders and local government officials were considering increasing security on school buses.
CNN's Sheila Upadhya and Dakota Flournoy contributed to this report