POLICE have released images of the 1.5kg of what is believed to be Semtex plastic explosive found at a block of flats in north Belfast.
Detectives said on Tuesday it was too early to link the discovery to any particular group but described it as "significant".
Police said the explosives were found at the Maeve House tower block in the New Lodge area on Monday following a report from a member of the public.
There was said to be enough to make three under car booby-trap bombs.
PSNI Chief Superintendent Chris Noble said: "These items will now be subject to a detailed forensic examination.
"Until this has been completed, it is too early to link these items to any particular group.
"Our investigations are currently ongoing and we are following a number of lines of enquiry.
"This was a significant recovery and we want to make sure that we gather every single piece of available information to assist us with our inquiries."
Mr Noble added: "This seizure demonstrates that when people provide us with information, we will act on it to ensure everyone in our community is kept safe."
Deputy First Minister Martin McGuinness said he was "disappointed but not surprised that there are still people within our society who believe that they have the right to attempt to point us all back to the past through attempts to kill people".
Justice minister Claire Sugden said it was "incomprehensible that this material was found in a residential area".
The Police Federation for Northern Ireland said the discovery "points to a ramping up of the dissident republican terrorist threat against police officers".
Chairman Mark Lindsay said: "What is most worrying is how did semtex come to be discovered in a block of flats in the New Lodge area? Where did it come from? Was it old stock?
"These are legitimate questions to ask and I would like to be given some direct answers. Our officers deserve no less."
Last month an armour-piercing improvised rocket, two anti-personnel mines, pipe bombs, magazines and ammunition for an assault rifle, bomb component parts and command wires were found in woodland near Larne, Co Antrim.
In March, police also found bomb-making parts and explosives at the Carnfunnock Country Park near Larne.
The find at Maeve House comes two years after a similar discovery at the flats.
