Gardai are now working directly with authorities in London after all three explosive devices found in the city yesterday were likely sent from Ireland.
The devices, which did not appear to be very sophisticated, were found at Heathrow Airport, Waterloo Station, and London City Airport.
Officers suspect that the packages might be linked to New IRA activities here. The group is suspected to have carried out the bomb attack in Derry in recent weeks.
Concerns have been raised that this activity could have a direct link to a possible hard border being proposed for Northern Ireland because of Brexit.
The two police forces are working motives over the coming days.