The deaths of two women police officers in Greater Manchester are "a terrible reminder of the risks that police officers face every day to keep our communities safe", the Home Secretary has said.
Theresa May said the killings of the unarmed officers, who were attending a routine incident in Tameside, were "deeply shocking".
One of the country's most wanted men, Dale Cregan, handed himself in to a police station soon after the incident.
Mrs May said: "This is a deeply shocking incident and a terrible reminder of the risks that police officers face every day to keep our communities safe."
Shadow home secretary Yvette Cooper said: "This is a painful demonstration of how police officers put themselves in harm's way every day to protect the public."
President of the Association of Chief Police Officers, Sir Hugh Orde, said: "Whenever police officers and staff lose a colleague that loss is felt right across the police family. The thoughts of everyone in policing are with colleagues in Greater Manchester Police, family and friends of the two officers at this time."
Ash Rathband, whose police officer father David was shot and blinded by gunman Raoul Moat, called for police to be armed after the murders.
Pc Rathband was found hanged at his home in Blyth, Northumberland, in February, having been blasted in July 2010 while on duty, sitting unarmed in a traffic patrol car.
His son tweeted: "It's time for police to be armed in my opinion."
His view was echoed by Pc Rathband's twin Darren, who said: "Give them more than a bloody piece of plastic and some spray. Tragic!"