At least five people have been attacked at a GP surgery in Milton Keynes, where staff declared a major incident.
Emergency crews were called to Parkside Medical Centre in Whalley Drive, Bletchley, at about 09:00 GMT.
Thames Valley Police said two members of staff and three members of the public were hurt. A man is being held on suspicion of multiple assaults.
South Central Ambulance Service said two people had been taken to hospital but there were no serious injuries.
The surgery has been closed until further notice and a post on its Facebook page claimed eight people had received injuries.
“Due to a major incident at Parkside Medical Centre we are closed until further notice,” it added.
“We are deeply upset by this incident and wish everyone involved a speedy recovery.
“The wellbeing of our patients and staff is paramount at this time and measures are currently being put in place to offer support to anyone affected by the event today.”