The responsibilities of the Garda Síochána Special Detective Unit include;
• The investigation of threats to state security and the monitoring of persons and organisations who pose a threat on both national and international fronts
• Counter-terrorism operations (specifically targeting dissident republicans and Islamic extremists)
• Armed response to serious incidents
• Security for movement of weapons, ammunition, and large cash-in-transit shipments
• Operation of the Witness Security Programme
• Presidential, ministerial and diplomatic protection, physical security for visiting VIPs
The Garda Emergency Response Unit (ERU) is the national armed tactical intervention unit of the Gardaí, and a subsection of the Special Detective Unit.The ERU's manpower is approximately 100 full-time officers, who are trained and equipped for a range of situations which other Garda units may be unable to deal with. The SDU and ERU carry out joint operations.
The Garda Counter-Terrorism International (CTI) unit was established in 2014 as a dedicated section of the SDU to identify and monitor Islamic terrorism threats and share intelligence with international security and law enforcement agencies on this issue. The Garda CTI has up to 50 full-time members who operate over 5 shifts. This section has its own surveillance teams and informants, and reports directly to the Garda Commissioner.The Counter-Terrorism Domestic (CTD) section deals with homegrown terrorism.
The Garda Hostage Negotiation Section (HNS), officially formed in 2007, is a subdivision of the Garda SDU. It is headed by an experienced Detective Superintendent, who cannot be identified for operational reasons.