Facebook has activated its Safety Check feature following the horror incident
Metropolitan police confirmed two incidents are terror related after a van mounted the pavement on London Bridge, ploughing into pedestrians, before reports of gunfire and stabbings near Borough Market.
Much of the area near the City of London has been locked down by armed police following the incident.
One witness comforting her distraught friend told our reporter at the scene: “We saw a vehicle mow down like five or six people.”
Facebook Safety Check can also be used to check-up on friends and family
Now Facebook has activated its Safety Check feature in London.
To find help in Safety Check, go to Safety Check on your iOS or Android device and click Find Help.
Facebook users can also browse a map view or scroll through existing posts on the main Safety Check page to see what kind of other help people in the area are offering.
The online tool allows Facebook users in nearby area to mark themselves as "safe" – letting loved ones know that they were unharmed in the incident.
Safety Check can also be used to check-up on friends and family.
Following an update to the feature, which was rolled-out earlier this year, Safety Check can also now let people locate and give help during a crisis.
Dubbed Community Help, the new functionality offers food, shelter and transportation following a crisis.
London Bridge terror: Scenes as armed police respond Sun, June 4, 2017
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At least two people have died after being after reportedly being struck by a van on London Bridge on Saturday night.
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Armed police responding to the incident at London Bridge
Some users have been offering refuge to people affected by the incident who cannot get home.
Facebook said it included the new feature after seeing people rush to offer similar services in posts and Facebook Groups following a disaster, so it decided to formalise the service.
Posts made via Community Help can be sorted by category and location and people will be able to message others directly to “connect” after a crisis, Facebook confirmed.
The Holiday Inn on Bankside has reportedly been evacuated following the horrific incident.
Witness Tony Murphy told Sky News there was “gunfire” following the incident.
There have been at least two fatalities in the horror incident
He said: “About half an hour ago there was tremendous gunfire that started.
“I thought at first it was fireworks. That was the first instance and only afterwards the emergency started but the whole incident started with gunfire it was significant gunfire, it went on for 10 minutes.”
Police have advised people to keep away from the area.