There are fears for a young Brisbane woman who became separated from her friends on London Bridge during the weekend terror attack.
Family and friends have made a social media plea to help find Sara Zelenak, 21, who has not answered her phone since the attack, despite calls and texts from worried friends and family.
Ms Zelenak became separated from her friends on the bridge when a van hit a number of pedestrians just after 10pm on Saturday (London time).
It is believed she may have dropped her phone while running from the scene of the attack.
Fairfax Media understands Ms Zelenak's friends in London are working with authorities to try to find her.
The attackers fled on foot to Borough Market, where they began stabbing people. Four Australians are "directly affected", including Candice Hedge who was stabbed in the neck.
Ms Zelenak works as a nanny in London, and is known to call her mother in Brisbane every day.
A Facebook post written by a family friend titled "Missing from London Terror Attack" has been shared more than 500 times.
"Dear friends please can I ask you to share this post. My friend's daughter, Sara Zelenak, was last seen on London Bridge and was witness to the terror attacks," the post reads
"She got separated from her friends and has not been seen since. Her phone has rang with no reply and now the battery must have gone.
"She is Australian aged 21 with long blonde hair. She calls her mum daily. It's been over 24 hours with no news from the consulate. We were hoping the 3rd Australian reported would be her, but it's not.
"She is based in London. Please share with as many people as possible especially if you have friends down south. Thank you for your help."
This Facebook post has since been removed.
In another post, on Monday evening, a friend said Ms Zelenak had not been heard from in more than 24 hours.
"This is my beautiful Australian friend Sara," the post reads.
"She went missing after witnessing the attack on Saturday night, last seen on London Bridge. She got separated from her friend and we believe she dropped her phone in the chaos and now it is flat.
"The authorities have already been notified. If anyone has seen her or knows of her whereabouts please let me know. I know she did have quite a few Aussie friends in London so maybe you guys know something more.
"We all want to make sure she is safe and need to get her home to her family."
Another of Ms Zeleank's friends, Sam Hetherington, also posted a plea on social media on Monday evening.
"PLEASE SHARE!!
"My best mate Sara Zelenak hasn't been in contact with her friends or family since terrorist attacks in London!
"If you or anyone is in London and sees this lovely face or knows any information on her whereabouts please message Julie Wallace or even myself to pass onto Julie so we know she is safe!"
Friends of Ms Zelenak's family have created a GoFundMe page to raise funds for the family to fly to London.
Seven innocent people were killed and 48 people hospitalised following the two terror attacks. The three attackers were shot dead by police.
Another family friend shared the post and wrote: "This is my friend's daughter, I am good mates with Mark (her husband). Told Mark today you guys live in London and that you would help in any way you could (be it probably there isn't a lot you can do)."
Prime Minister Malcolm Turnbull confirmed on Monday that four Australians were caught up in the attack. Two have been identified – Candice Hedge from Brisbane, and Darwin man Andrew Morrison. Both were hospitalised after the attack.
The remaining two Australians are yet to be identified, however it is understood one of them is seriously injured and the other person unaccounted for.
The Department of Foreign Affairs and Trade was unable to comment on Ms Zelenak's disappearance.
It is understood DFAT is providing consular assistance to all Australian families it has been made aware of who have been affected by the attacks.