Armed police sealed off a Devon street after a man with a number of knives refused to come out of a house.
Officers say the man, who was alone in the property, was supposed to be attending hospital but was refusing.
The 46-year-old is alleged to have shown a number of knives to officers, and then shut himself inside the house. He made no "specific threats" at any time, a police spokesperson said.
Police, who were called to the scene in Furland Close, Plymstock, near Plymouth, just before 2pm on Saturday, authorised an "appropriate" armed response.
The area, off Reddicliff Road, was contained and police were able to negotiate with the man.
He remained in the property for four hours before eventually coming out.
Police say he was detained on his doorstep, arrested on suspicion of affray and was taken to Charles Cross police station where he remains in custody.
Witnesses reported 14 police vehicles and three ambulances at Reddicliff Road and Furland Close.
Police were called at around 2pm, and the entourage gradually built until there was a substantial presence by 5pm. Neighbours say police had riot shields.
Police say there were a large number of officers at the scene, partially because of the nature of the incident, but also because of shift changes.
Officers say there were no injuries.
It is believed the man was supposed to be attending hospital for help with mental health issues and police were alerted by a member of staff.
