Facebook Safety Check

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

What actually happened in Bangkok

The Safety Check, first introduced in October 2014, allows Facebook users to spread the word that they are safe in the wake of a natural disaster or a crisis, and allows searches for those who might be in the affected area.

"Waking up this morning, I was horrified to hear about the shooting in Orlando," Facebook chief executive Mark Zuckerberg said on his official account.

"My thoughts and prayers are with the victims, their families and the LGBT community."