The 47-year-old was detained following Serious Crime Branch searches at Maeve House in the New Lodge area on Wednesday evening and Thursday morning.Suspected high explosives were discovered in a flat. Police said it is not possible to be specific about the high explosives or the quantity involved other than to describe both as "significant".District Commander Chief Superintendent Nigel Grimshaw said: "It beggars belief that quantities of high explosives could be stored in a block of flats in which hundreds of people are living."I welcome the fact that colleagues from Serious Crime Branch have taken this material out of circulation. It has been removed for detailed examination but we believe it to be high explosives."The man is being questioned at Antrim PSNI Station.District Commander Chief Superintendent Nigel Grimshaw continued: "District officers will continue to work with colleagues and the community to ensure that everyone is kept safe from the threats posed by those individuals and groups who would seek to inflict death and injury."The search operation is continuing. We apologise for any inconvenience or disruption but we need to ensure that everything has been done to keep people safe."