Three men arrested in connection with a dissident republican shooting in Garrison, Co Fermanagh have been released without charge.
One of the men released had been arrested by Irish police in Dooard, Co Leitrim.
Two of four men detained by the PSNI after police exchanged fire with suspected dissident republicans on Saturday night have also been released.
Two other men, aged 41 and 26, are continuing to assist PSNI detectives with their enquiries.
Read Ken Reid's blog: Dissident warning
A Catholic police officer who lived in the village, but was not home at the time, was the target. It is understood an undercover police operation foiled the murder bid.
Chief Constable Matt Baggott said that his officers fired two warning shots, which are being investigated by Police Ombudsman Al Hutchinson. He confirmed his officers had been fired at once during the exchange.
The Assembly united on Monday to condemn the latest attempts to derail the peace process.
The DUP's Arlene Foster praised police who had to open fire as they moved in to prevent the Fermanagh attack and said a young recruit had been targeted for opting to serve the community.
"There must be a message coming from this place today, and that message must be a strong and united one," she said.
"We need strong political leadership from this House and indeed outside of this House."
Sinn Fein Fermanagh-South Tyrone MP Michelle Gildernew also condemned the dissidents.
"The people carrying out these attacks are doing so against the expressed wishes of the Irish people and to wreck the advances of the peace and political process," she said.
UUP leader Sir Reg Empey called for talks on the devolution of policing and justice powers to forge an agreed way forward for the Assembly.
"I think until that happens, the vacuum that the terrorists are exploiting at the moment will remain," he said.
SDLP Mark Durkan said dissident activity struck at the heart of democracy and also called for the devolution of policing powers to demonstrate political unity.
He warned said dissidents would not succeed: "Our resolve is much greater than their malice."
In a separate incident, a 400lb bomb partially exploded after a vehicle broke through a barrier outside the headquarters of the Policing Board in Belfast.
Nobody was hurt but two men were seen escaping from the area at Clarendon Dock on Saturday night.
Chief Constable Matt Baggott said Saturday's attacks were designed to derail political progress.
"We have said from day one that the terrorist situation is severe. We have substantial resources being put into investigating and thwarting these attacks," he said.
"This attack is an attack on the well-being of everybody in Northern Ireland, this is not about an attack on policing or the Policing Board, this is an attack on young people and young people's future."
A car was found burned out nearby in the staunchly republican New Lodge area of the city and police are investigating whether there was any link with the attack on the Policing Board.
Earlier this month the Independent Monitoring Commission (IMC) reported that the dissident republican threat was at its highest level for almost six years.
The IMC said the two main dissident republican groups, the Real IRA and the Continuity IRA, were working more closely together to increase the threat posed to security forces.
On March 7 the Real IRA killed sappers Mark Quinsey, 23, and Patrick Azimkar, 21, at Massereene Army base in Antrim.
Two days later the Continuity IRA shot PSNI Constable Stephen Paul Carroll in Craigavon, County Armagh.
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