A 21-year-old Israeli student was attacked and killed in Melbourne, Australia while speaking with her sister on the phone, police say.

The body of Aiia Maasarwe, 21, was found near LaTrobe University in the city's north. She had taken a tram home late on Wednesday after a comedy show.

Her sister "heard the sound of the phone falling to the ground and heard some voices", officer Andrew Stamper said.

Police are searching for the killer.

They have not ruled out the possibility that Ms. Maasarwe was sexually assaulted, Melbourne's Age newspaper says, with known sex offenders "an active line of inquiry".

"Our presumption at this stage is that this was a random attack and opportunistic." Detective Inspector Stamper told reporters.

Ms. Maasarwe's sister, worried about Aiia, is reported to have called Australian police around the same time the body was found on Thursday morning outside a shopping centre.

A black cap emblazoned with "1986" and a grey t-shirt were found near the crime scene, and are being forensically tested. Police are also scouring CCTV footage for clues.

"Someone in the community knows about this. Someone has gone home on Tuesday night, or in the early hours of Wednesday morning, maybe with blood on them, missing items of clothing. Somebody knows about this," said Mr. Stamper.

Ms. Maasarwe was a student of Chinese and English at a university in Shanghai, her uncle, Abed Katane, told Israeli media. She was on an exchange programme at LaTrobe, he said.

"She was an excellent student, full of life. She wasn't in a very dangerous country at all, and yet we are still receiving such a painful message," Mr Katane told the Haaretz newspaper.

Aiia Maasarwe's father has arrived to identify the body, which the Israeli embassy said it would assist with returning to Israel.

Last June the killing of 22-year-old comedian Eurydice Dixon sparked fresh anger and debate about violence against women in Australia.

Ms. Dixon was raped and killed while walking home after a performance in Melbourne.

That followed a similar case in 2012, when Irish woman Jill Meagher was raped and murdered in Melbourne's inner north while walking home - prompting mass rallies to remember her and raise the issue of women's safety.

Australia's human rights commission has said that the country has "a disturbingly high rate of violence against women".

According to government figures, one in five women, and one in 20 men, have experienced sexual violence or threats since the age of 15.

Melbourne, Australia's second-largest city, draws large numbers of foreign students to its many universities. More than 200,000 students came to the state of Victoria in 2017 to study, according to the state government.