US Secret Service agents are checking out secure accommodation in hotels along the Border as part of the massive police operation in the run-up to the G8 summit of world leaders in June.
Hotels in four southern counties, Cavan, Monaghan, Leitrim and Donegal, are expected to be used by some of the delegations arriving for the summit, which will be held across the Border at the Lough Erne golf resort in Enniskillen.
Agents have already been here to liaise with the gardai on the security that will be provided on this side of the Border during the summit.
Apart from those who will be staying in hotels that have been deemed suitable by security experts, it is expected that some of the delegations could fly into Dublin rather than Belfast.
Officers from the crime and security branch at Garda Headquarters in the Phoenix Park are keeping in regular touch with the PSNI team in charge of planning the local protection for the visitors.
It is expected that up to 2,500 police officers from British forces will be deployed in the North to supplement the locals and PSNI officers are travelling to Britain to provide specialist training on the potential threats from homegrown terrorists.
Dissident republican groups are expected to attempt to stage a so-called "spectacular" because of the huge interest in the summit around the world.
Already, a group, who style themselves as Oglaigh na hEireann, has claimed that a beer keg bomb found abandoned on the Derrylin Road, Enniskillen last weekend was intended for an attack on the Lough Erne resort.
Police officers felt it was more likely that the terrorists were planning to use the bomb for an attack on a police station 16 miles away at Lisnaskea.
The dissidents are not expected to stage any attacks on the summit as they do not have the capacity to penetrate the security ring that will be thrown around the event and know they would be forced out of existence by the backlash if world leaders were targeted.
But there are concerns they could attempt to murder members of the security forces in the run up to the event and gardai are being asked to play a key role here.
Governments in the US, the UK, France, Germany, Italy, Japan, Canada and Russia are represented in the G8 and leaders such as US President Barack Obama are targets for international terrorists.