
Police said the 47-year-old man, believed to be mentally unstable, pointed a 21cm knife at worshippers in the surau in the 2.30pm incident.
City police chief Mohd Zaidi Abdullah said a police team found the man still acting aggressively when they went to the surau after receiving a distress call.
He said a policeman sustained cuts to his fingers before the man was subdued. No one else was hurt.
Zaidi said the suspect could have acted in a threatening way because he had not taken his medication. He had with him an appointment card issued by a psychiatric hospital here.
The injured policeman was treated at the airport clinic.