Facebook users in Bangkok were falsely alerted to an "explosion" in the Thai capital, after the social network activated its Safety Check feature.

It allows Facebook users in danger zones to mark themselves as safe, but in this instance was triggered by a protestor throwing firecrackers.

Facebook said it relied on a "trusted third party to confirm the incident".

But the way it was labelled misled many online as people started sharing false news of a blast.

Facebook has recently faced criticism for allowing fake news to proliferate.

'Community activated'

On Tuesday, a protester threw small firecrackers at a government building in Bangkok.

According to Facebook, this triggered the Safety Check feature at about 21:00 local time which created a page titled "The Explosion in Bangkok, Thailand" and people started marking themselves as safe.

The page also pulled in links referencing a BBC article about an explosion in Bangkok, but it was an article from 2015 about the explosion at the Erawan shrine. The safety check feature was later deactivated.

When Facebook first introduced the tool in 2014, it would activate the feature manually. In November, Facebook changed course and said it would now be activated "by our community".

Now, a third-party source alerts Facebook when an incident occurs. The social platform then searches to see if users in the area are discussing the incident.

If enough users are referencing the incident, those in the area are invited to mark themselves as safe.

According to Facebook, the title of the safety check is taken from the alert provided by the third-party source.