The friends of a Sydney mother who travelled to the Middle East to join the Islamic State militant group have confirmed they have been contacted by police about her whereabouts.

Jasmina Milovanov, who calls herself Assma Abdullah, left her two children with a babysitter last month, telling friends she needed to travel to Queensland to buy a new car.

A close friend to the 26-year-old said authorities visited family and friends after it was revealed she had left the country.

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“The authorities were investigating those of us closest to her. I had police come to my house wanting to speak to me,” the friend said.

“None of us had any idea but she’s obviously been contemplating this for a while.”

Sources close to the 26-year-old told the ABC they could not contact her when she did not return for her children.

They first became aware of Ms Milovanov’s location when they received a message via Facebook that she had travelled to the Middle East.

“She never came back [but] we received a message on a Monday saying she was in Syria,” a source said.

A Melbourne woman who travelled to Syria last year to marry her boyfriend sent a message to Ms Milovanov’s friends.

“Zehra Duhman gave us initial confirmation that she’d gone over there. She said Assma [Jasmina] is safe. She recently made hijrah to Sham [Syria]. She’s being looked after well.”

Another close friend, who does not want to be identified, said Ms Milovanov often posted on social media about finding a husband.

“What we believe is Assma really wanted to get married, she was very lonely … we think that’s how they’ve encouraged her to go,” the friend said.

“She’s not a terrorist. I don’t believe she’s gone over there to fight.”

‘It’s blowing my mind because she was so normal’

Ms Milovanov borrowed $2500 which friends believe was used to fund her trip to Syria.

“None of us had any idea. She never said a word,” a friend said.

“We are in shock. For her not to come home to her kids … they were her whole world.”

One person who knows Ms Milovanov said they had been interviewed by the authorities but was not able to tell them much and that they were surprised by her disappearance.

“I always read stories about others who’ve gone over to Syria and think how could people around them not know,” they said.

“None of us had any idea. It’s blowing my mind because she was so normal.”

NSW Police said that as the matter was a current investigation by officers attached to the joint counterterrorism team, it was not appropriate to comment.

It is understood that Ms Milovanov’s children are being looked after by their father and his family.

Meanwhile, a 23-year-old Brisbane man has also left Australia, but it’s believed he wanted to fight against ISIS militants.

Ashley Dyball has reportedly posted several times on Facebook, saying he was headed for the “front line tomorrow #f***isis”.

Another post, featuring an image of him dressed in camouflage gear and holding an assault rifle, said: “No news is good news. Miss everyone from home hope your (sic) all well #YPG #F***THEISLAMICSTATE”.

Media reports said Mr Dyball may have links with the Kurdish People’s Protection Units fighting Islamic State militants in Syria and Iraq.

-ABC, with AAP