A counter-terror investigation has been launched after three small explosive devices were found at buildings at three major transport hubs in London.

Police responded to reports of suspicious packages at Waterloo train station and office buildings at Heathrow and London City airports on Tuesday.

All the packages were A4-sized white postal bags containing yellow Jiffy bags and appeared capable of igniting a small fire when opened, police said.

?? Licensed to London News Pictures. 05/03/2019. London, UK. The scene at Waterloo Station as police deal with a suspicious package. Earlier reports said the station has been evacuated, but police state that trains are running as normal. Similar incidents have been reported at Heathrow and London City airport. Photo credit: Peter Macdiarmid/LNP
Police said this afternoon that the devices located at Heathrow Airport, London City Airport and Waterloo train station were all in A4-sized white postal bags containing yellow Jiffy bags (Picture: LNP)

Scotland Yard said officers are treating the incidents as linked and are keeping an open mind regarding motives.

No one has been injured in the three incidents, police said.

Officers received a report of a suspicious package at The Compass Centre, a building near Heathrow Airport boundary, shortly before 10am.

A statement from Scotland Yard said: ‘The package was opened by staff at the building, causing the device to initiate.

‘This resulted in part of the package burning.’

The building was evacuated as a precaution and specialist officers attended the scene to make the device safe.

Police said the building remains closed as enquiries.

Police officers secure the scene where suspicious package was found near Waterloo railway station in London, Britain March 5, 2019. REUTERS/Peter Nicholls
Police officers secure the scene where suspicious package was found near Waterloo railway station (Picture: Reuters)

A Heathrow spokesman earlier said that flights and passengers were not affected by the incident.

British Transport Police were called to reports of a suspicious package in the post room at Waterloo station at 11.40am.

The package was not opened and specialist officers again made the device safe.

Police were also called to a report of a suspicious package at Aviation House at London City Airport shortly after midday.

In a statement, Scotland Yard said: ‘The Met Police Counter Terrorism Command has launched an investigation after three suspicious packages were received at buildings in London today, Tuesday, 5 March.

‘The packages – all A4-sized white postal bags containing yellow Jiffy bags – have been assessed by specialist officers to be small improvised explosive devices.

'Suspicious packages' investigated at Waterloo Station in London Featuring: Police Where: London, United Kingdom When: 05 Mar 2019 Credit: Luke Dray/Cover Images **All usages and enquiries, please contact info@cover-images.com - +44 (0)20 3397 3000**
British Transport Police were called to reports of a suspicious package in the post room at Waterloo station at 11.40am (Picture: Luke Dray/ Cover Images)

‘These devices, at this early stage of the investigation, appear capable of igniting an initially small fire when opened.

‘The Met Police Counter Terrorism Command is treating the incidents as a linked series and is keeping an open mind regarding motives.

‘At approximately 9.55am the Met Police received a report of a suspicious package at The Compass Centre, Nelson Road, Hounslow. The package was opened by staff at the building, causing the device to initiate. This resulted in part of the package burning.

‘No one was injured. The building was evacuated as a precaution. Specialist officers attended and made the device safe. The building remains closed as enquiries continue. The building is not based at Heathrow Airport, and flights have not been effected by this incident.

‘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.

?? Licensed to London News Pictures. 05/03/2019. London, UK. Emergency services on the scene at London City Airport where police were called to reports of a suspicious package. Suspicious packages have also been found at Heathrow Airport and London Waterloo Station. Photo credit: Rob Pinney/LNP
Emergency services on the scene at London City Airport (Picture: LNP)

‘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 12.10pm police were called to a report of a suspicious package at offices at City Aviation House, Royal Docks, Newham.

‘Staff were evacuated from the building as a precaution. The package was not opened and no one was injured. Specialist officers attended and made safe the device. The building has been reopened.

‘As a precaution, DLR services to London City Airport were suspended but are now fully operational. Flights to and from the airport have not been affected.

‘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. Enquiries are ongoing.’