Counter-terrorism police have launched an investigation after an improvised explosive device was sent to the post room at Waterloo Station and two other locations in the capital.
The Met says that the packages – all A4-sized white postal bags containing yellow Jiffy bags – have been assessed by specialist officers to be small improvised explosive devices.
"These devices, at this early stage of the investigation, appear capable of igniting an initially small fire when opened," said a Scotland Yard spokesman.
"The Met Police Counter Terrorism Command is treating the incidents as a linked series and is keeping an open mind regarding motives."
The first package was reported to police at 9.55am on Tuesday at the Compass Centre near Heathrow Airport.
At approximately 11.40am British Transport Police were called to reports of a suspicious package in the post room at Waterloo Station. The package was not opened. Specialist officers attended and made the device safe. No one was injured.
The station was not evacuated however cordons are in place at a small area outside the station on Cab Road. Train services are continuing to operate as normal.
At approximately 12.10pms police were called to a report of a suspicious package at offices near London City Airport.
The Met Police has issued advice to transport hubs across London to be vigilant for and report suspicious packages to police.
No arrests have been made and investigations continue.
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