NO manhole cover is being left unturned as gardai secure the routes to be used by Queen Elizabeth and US President Barack Obama in their upcoming visits here.
Manholes are being checked and then sealed as part of the massive operation to guarantee the safety of the two VIPs.
Yesterday, they carried out the checks along the quays in Dublin city centre. Gardai also continued to interview people living along the route, taking note of their name, phone number and car registration plates.
Senior anti-terrorist officers are examining every option that might be available to home-grown or international assassins to carry out an attack.
Garda leave has been restricted during the visits and an estimated 6,000 members of the force and Defence Forces personnel will take part in the nationwide operation to deter an attack.
The six garda regional commanders are responsible for arrangements in their areas and are liaising closely with Assistant Commissioner John O'Mahony, who is in charge of the crime and security branch.
A dossier has already been compiled by the Garda Special Branch on dissident republicans who might attempt to cause trouble during the queen's visit and monitoring of suspects has been steadily increased.
A small group of suspected sympathisers of international terror networks, such as al-Qa'ida, are also under surveillance.