BREAKING Two unarmed female police officers were killed while attending a "routine incident" today which led to the arrest of one of the country's most wanted men, Greater Manchester Police said.
Cregan was being sought over separate gun and grenade attacks that killed father and son David and Mark Short.
A £50,000 reward had been offered for information leading to his arrest.
One of the officers died at the scene in Hattersley, police said. The second was critically injured and died afterwards.
Cregan had been the subject of a huge manhunt after the murders of David Short, 46, and his son Mark, 23.
David Short was killed at his home in Folkestone Road East, Clayton, Manchester, on August 10, while Mark was gunned down at the Cotton Tree pub in nearby Droylsden, on May 25.
Home Secretary Theresa May said the killings were "a terrible reminder of the risks that police officers face every day to keep our communities safe".
Shadow home secretary Yvette Cooper said: "We should pay tribute to the bravery of the two officers today who have given so much in their work to keep us safe, and our thoughts are also with their friends and colleagues in Greater Manchester Police. This is a tragedy that will be felt throughout the country."
Sir Hugh Orde, President of the Association of Chief Police Officers, added: "The death of two female police officers in Greater Manchester is deeply sad news for the police service. The two unarmed officers were responding to a routine call when faced with a dangerous and deadly situation...
"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."
LATEST Police said the two officers had been attending an incident at Abbey Gardens in Hattersley, Tameside, shortly before 11am today. The force did not give any details of the incident but described it as "routine".
Police said there were reports that shots were fired and the two officers suffered serious injuries.
Greater Manchester Police Assistant Chief Constable Garry Shewan said: "I understand that the community will be fearful as they hear news of what has happened this morning. We have armed officers patrolling the area and we will aim to keep people updated as much as we can."
A fleet of vans and ambulances are parked at the top of the road and a police helicopter is hovering overhead.
A 27-year-old woman, who did not want to be named, said her ex-boyfriend witnessed the shootings. She said it happened outside the address of a man who, she said, knew Cregan.
She said: "He (her ex-boyfriend) was a bit shook up when I saw him."
She said he was walking back from the doctor's when he heard someone he knew shout to him, adding: "Then someone has come outside the house ... and shot two officers and then he threw a grenade in the garden. He (her ex-boyfriend) said the officers hit the floor."
Paul McKeever, chairman of the Police Federation of England and Wales, said: "This tragedy makes us all stop and reflect on the very real dangers police officers face every day serving their local communities...
"These extremely courageous officers have sadly paid the ultimate price for their selfless actions and no words can express our regret nor comfort to their families. The entire police service throughout the UK mourn their loss...
"I know that my colleagues in Greater Manchester Police Federation will be doing everything they can to offer support and counsel to the relatives and colleagues of these brave officers."
Derek Barnett, President of the Police Superintendents' Association of England and Wales, said: "Today once again we have seen how police officers pay the ultimate price in losing their lives to protect the public...
"Whilst we still don't know the full circumstances, this tragic situation demonstrates the uniqueness of the office of constable, a duty not to walk away from danger. It also serves as a reminder of the risks that officers face on a regular basis...
"At the beginning of their tour of duty these two officers would have had no idea what lay ahead of them. I'm sure few words will offer true comfort to the families, colleagues and friends at such a difficult time, but our thoughts and prayers are with them."
Local window cleaner Warren Shepherd was on his rounds in Hattersley close to where the officers were shot.
He said: "I just heard gun shots, bang, bang, bang - around ten of them, then a pause and a big explosion. I went around the back of the houses to see what happened and there was a police car that looked empty. There was people, neighbours stood around there and one of my customers said, 'They've been shot! The police officers have been shot!'"
Mr Shepherd went on: "Everybody was in shock and couldn't believe it. It must have been a matter of minutes, more police cars came and an ambulance came."
Mr Shepherd said the house where the incident took place was the former home of a customer of his, an elderly woman who died about six months ago.
The property, a council house, had been left empty but there had been some recent activity, with the windows covered in whitewash suggesting the house was being decorated.