Northern Ireland police issue Easter terror warning
Police in Northern Ireland have warned the public to be vigilant over the Easter weekend because of the "severe threat posed by terrorists".
Security checkpoints and patrols are being stepped up as a result.
On Saturday, detectives investigating dissident republican activity said they found a "substantial" amount of guns and ammunition in south Armagh.
Three men have been arrested in connection with the discovery on Friday near Keady.
In seperate searches on Saturday a large quantity of bomb making equipment was also discovered.
The Police Service of Northern Ireland said the arrests were a joint operation with police in the Irish Republic.'Single objective'
The BBC's Mark Simpson in Belfast says it is feared dissident republicans are preparing to attack police officers over the Easter holiday period.
Three weeks ago Northern Ireland police officer Constable Ronan Kerr, a 25-year-old Catholic, was killed in a car bomb attack and it is now believed there may be other attacks.
The police have warned the public to be vigilant and asked for more help in catching those involved in violence.
The warning from police in Northern Ireland about the rising threat from dissident republicans was a stark reminder of how much work still needs to be done in the peace process.
When the Good Friday Agreement was signed 13 years ago, it was envisaged that the violence would now be over.
Instead, the statement issued on Good Friday by the police in Belfast warned of a "severe threat posed by terrorists".
They may be small in number, but they are armed and dangerous.
The increase in dissident activity coincides with the Northern Ireland Assembly election campaign, and preparations for next month's first visit by the Queen to Dublin.
Both events demonstrate how Northern Ireland politics have matured and stabilised - the dissidents do not want normality, they want instability.
The message from the police to people in Northern Ireland is "help us to protect you".
A PSNI spokesman said: "Dissident terrorist groups are continuing to identify officers and target them with the single objective of killing them.Election campaign
"And, in so doing, their reckless actions will also put the lives of our wider communities at risk.
"We ask for patience with their [the public's] officers if they are inconvenienced due to police activity."
The recent increase in dissident republican activity coincides with the Northern Ireland Assembly election campaign.
The dissidents do not have a political wing fighting the election and they seem interested only in violence, our correspondent says.
Police said they had made a "number of significant arrests" in the south Armagh area in relation to dissident republican activity.
Officers said the arrested men were taken to Antrim serious crime suite for questioning and the investigation was continuing.