The US embassy in London is reported to be in a state of lockdown with those inside told to duck and move away from windows.

Photos shared online by people inside the building show them crouching on the floor and sitting back against the walls, as well as police at the scene.

One witness, who lives close to the embassy and can see the building from their window, told MailOnline there are armed police and sniffer dogs patrolling the area.

In a video shared with MailOnline, a police officer could be seen cordoning off the area in Nine Elms, London.

Social media users at the scene also reported that there were “many armed policemen shouting”, although what caused the security threat remains unclear.

source dailymail.co.uk