All Garda leave is being cancelled in Dublin in the days before the 1916 centenary celebrations of the Easter Rising.
This follows a bomb attack on a prison officer in Northern Ireland, and a warning by the Police Service of Northern Ireland (PSNI) that dissident republicans want to kill members of the security forces in the run up to the celebrations.
Garda Commissioner Noirin O’Sullivan pledged that every step would be taken to secure the safety of the public during commemoration events.
She said the threat posed by dissidents remained a top-security priority on both sides of the border, and Gardai were working closely with the PSNI in the wake of last Friday’s bomb attack which severely injured a prison officer in Belfast as he drove to work.
The bomb partially detonated under his van as he drove over a speed ramp. The 52-year-old father of three was later said to be stable in hospital.
In a statement to the BBC a dissident republican group calling themselves the New IRA said the officer was targeted because he was involved in training other guards at Maghaberry Prison, near Lisburn.
PSNI Assistant Chief Constable Stephen Martin said the threat from dissidents is “severe.”
“There are people within dissident republican groupings who want to mark the anniversary in an entirely sinister way, who want to kill police officers, prison officers or soldiers,” he said.
Northern Ireland’s First Minister Arlene Foster and Deputy First Minister Martin McGuinness said in a joint statement that it was a “disgraceful and despicable attack.”
In Dublin, up to 250,000 people are expected to line the streets during planned events.
A total of 2,300 serving personnel from the Defense Forces and 400 veterans will march in the parade, which is expected to be watched by a couple of hundred thousand people.
Garda assistant commissioner in charge of security and intelligence, John O'Mahony, pointed out that interventions by the Gardai had thwarted dissident terror plans for the visits of Queen Elizabeth and Prince Charles.