Gardaí have confirmed their assisting the Metropolitan Police in London following the discovery of three "small improvised explosive devices" earlier.
They were sent to staff buildings at three transport hubs across London - Waterloo train station, Heathrow and London City airports.
It's believed at least two of the packages had an Irish post stamp.
Staff at Heathrow opened the package “causing the device to initiate".
Police said this “resulted in part of the package burning" - however, nobody was injured.
The other two packages were not opened.
Officers in counter terrorism are treating the incidents as a linked series and is keeping an open mind regarding motives.
.@Metpoliceuk Counter Terrorism Command has launched an investigation after three suspicious packages were found at locations around London today - thankfully there have been no injuries. I would like to thank first responders for their swift actions to keep Londoners safe. pic.twitter.com/d3OVfy4uYn
— Mayor of London, Sadiq Khan (@MayorofLondon) March 5, 2019
The Minister for European Affairs Helen McEntee has condemned the actions of those behind the incidents.
She said: "It's completely unacceptable that that kind of action or those kind of actions would have any place in our society - whether it was intended to injure people or otherwise.
"I know the gardaí are working with the English police... Really [the incidents] need to be condemned by everybody, and whoever has done it needs to be caught and prosecuted."