An investigation has been launched after three packages containing explosives were found near major transport hubs in London.
The Metropolitan Police said the "small improvised explosive devices" found in A4 postal bags at Heathrow Airport, London City Airport and Waterloo station were "capable of igniting a small fire when opened".
Irish police have also joined the investigation as the Heathrow and Waterloo packages had Republic of Ireland stamps on them, with Met's Counter Terrorism Command treating it as a "linked series".
All locations were evacuated and no injuries reported, local media said.

7 killed as 6.3 magnitude earthquake hits northern Afghanistan
Hamas hands over three more hostage bodies
Israeli strike kills one in Gaza as sides trade blame for truce violations
UK police say mass stabbing on train not terrorist incident, two arrested
Israel urges Lebanon to disarm Hezbollah under ceasefire terms
Russian attacks on Ukraine kill two
Kenya landslide death toll rises to 22
Fire at store in northwestern Mexico leaves at least 23 dead
