Northern Ireland Secretary Theresa Villiers has described the murder of Northern Ireland prison officer David Black as a "cowardly and evil crime".
Making a statement to MPs on the murder on 2 November 2012, she said: "An attack on the prison service is an attack on all of us."
Two men have been arrested in connection with the fatal shooting of Mr Black, who was attacked in County Armagh on Thursday morning.
The father of two, from Cookstown in County Tyrone, was driving to work at Maghaberry Prison when he was shot on a stretch of motorway between Portadown and Lurgan.
The Police Service of Northern Ireland (PSNI) have said they believe dissident republican paramilitaries were responsible for the attack, which is the first murder of a prison officer in Northern Ireland for 20 years.
Mrs Villiers said there had been a "clear, united and resolute" response from the people of Northern Ireland and pointed out that the attack had also been condemned in the Republic of Ireland and the United States.
"There will be no return to the dark days of the past," she added.
Shadow Northern Ireland Secretary Vernon Coaker described the attack as "the cold-blooded, evil murder of an ordinary man going out his ordinary, decent business".
The DUP's leader in the UK Parliament, Nigel Dodds, praised Mr Black's family for calling for no retaliation for his murder.
He called on ministers to "urgently review the threat level" posed by terrorism throughout the UK.
Earlier this month, the government's assessment of the threat from dissident republicans in Great Britain was lowered from "substantial" to "moderate", though ministers insisted the threat in Northern Ireland remained "severe".
Mr Black's killing has also been condemned by Prime Minister David Cameron, Northern Ireland First Minister Peter Robinson and Deputy First Minister Martin McGuinness.
The two men arrested, one of whom is the prominent republican Colin Duffy, were detained in the Lurgan area in County Armagh on Friday morning.