Greater Manchester Police tweeted:
Manchester City FC flies its flag at half mast in memory of PC Fiona Bone and PC Nicola Hughes http://t.co/fZbkDhQO
Officers nationwide have offered cover to colleagues in Greater Manchester Police so they can attend the funerals of the two killed PCs.
Manchester's police chief said he expected "developments" in the next 24 hours over possible charges relating to the deaths of two officers.
Over 50,000 tributes have been posted to Greater Manchester Police's online book of condolence to the two killed officers and Facebook page.