There have been so many of these in the past few weeks that the theme might need it's own thread. From BBC News:
Five people have been stabbed in an attack at the Arndale Centre in Manchester city centre.
A man was seen "running around with a knife lunging at multiple people", according to one witness.
There are no reports of fatalities and a man in his 40s has been arrested on suspicion of serious assault.
Prime Minister Boris Johnson tweeted: "Shocked by the incident in Manchester and my thoughts are with the injured and all those affected."
Greater Manchester Police (GMP) said counter-terror officers were "keeping an open mind".
North West Ambulance Service said one patient had suffered "serious" injuries.