Published Saturday, 03 November 2012
US Secretary of State Hillary Clinton reacts to the murder of David Black (© Getty)
Mr Black, a 52-year-old father-of-two from Cookstown, was ambushed by gunmen while driving to work at Maghaberry along the M1 near Lurgan on Thursday morning.
A number of shots were fired at his black Audi A4 from a dark blue Toyota Camry with Dublin-registered number plates, which pulled up alongside.
Mr Black's funeral will take place on Tuesday, police confirmed.
It is widely believed that dissident republicans are behind the attack as they have been engaged in a long-running protest campaign against conditions in Maghaberry.
Mr Black, a long-standing member of the Orange Order, is the 30th prison officer to be murdered in Northern Ireland since 1974 - though the first for almost 20 years.
"There is no justification for this outrageous and cowardly act," Mrs Clinton said.
"I offer my sincere condolences to the family, friends and colleagues of Officer Black, who had a long and distinguished record of service."
The United States remains resolute in support of the people of Northern Ireland, who have condemned violence and embraced the path to peace and reconciliation.
Mrs Clinton has been a strong supporter of the Northern Ireland peace process for two decades, along with her husband, former president Bill Clinton.
She applauded "the swift efforts of the Police Service of Northern Ireland to bring the perpetrators to justice".
Three people are being questioned in connection with the attack. Two men aged 44 and 31, including prominent republican Colin Duffy, were detained in the Lurgan area on Friday morning.
A 29-year-old man was later arrested by Gardaí in Co Leitrim.
Meanwhile, a reward of up to £10,000 has been put up for information leading to the arrest and conviction of those responsible for the murder. Independent charity Crimestoppers is behind the reward fund.
Anyone with information about the attack is asked to contact the special incident room at Lurgan PSNI station on 028 38 315291 or Crimestoppers on 0800 555 111.
A book of condolence for Mr Black has been opened at the Burnavon Centre in his hometown of Cookstown.
The murder has been widely condemned by political leaders, including the First and deputy First Minister, Taoiseach Enda Kenny and Prime Minister David Cameron.