Police are not currently treating an incident involving a car outside the Natural History Museum as terrorism-related, The Independent understands.
Several pedestrians were left injured after a vehicle reportedly mounted a pavement outside the attraction in London.
A man was pictured being held down by passers-by and police said they had detained a man.
But while officers continue to investigate the circumstances surrounding the incident – and stress the situation could quickly change – no clear evidence has yet emerged that would suggest it was terrorist attack.
The Metropolitan Police has not given any further detail of the man detained.
A witness told The Independent: “I saw two cars, they crashed. Two men got out of one car and took one man from the other. That’s all I saw.”
Isis has advised supporters on how to carry out deadly vehicle rammings while intensifying calls for global terror attacks, as it continues to lose territory in Syria and Iraq.
The group encourages attackers to use a secondary weapon like a knife, as seen in Westminster and London Bridge, to cause maximum casualties after a crash.
Isis also tells supporters to make their allegiance clear during atrocities, either by shouting slogans, leaving letters and videos or displaying the group’s flag in their vehicles – none of which have yet been reported in this case.
Downing Street said the Prime Minister was being kept up-to-date on developments.