A man suspected of wounding five people with a chainsaw is still on the loose as a manhunt continues on the Swiss-German border.

Franz Wrousis, 51, who was described by police as dangerous, aggressive and mentally unstable, is accused of attacking two employees of a health insurance company in their office in Schaffhausen’s old town on Monday morning.

Two customers were treated for shock after they witnessed the attack, and another person was slightly injured during the subsequent police operation. Four of the five injured people have now left hospital.

A manhunt continues for Franz WrousisA manhunt continues for Franz Wrousis (AP)

One company employee, who was severely injured, is still in hospital, but not in a life-threatening condition.

Authorities said the suspect has previous convictions for weapons offences and has no fixed residence. In recent weeks he was seen in the forests near Schaffhausen.

Police are searching the region with helicopters and sniffer dogs.

Officers warned that Wrousis may be armed and asked anyone who sees him to contact police immediately, and to keep away from him. They also put out an international arrest warrant.

The incident happened in the old town of SchaffhausenThe incident happened in the old town of Schaffhausen (Ennio Leanza/AP)

Schaffhausen, a town of about 36,000 people north of Zurich, is near the Swiss-German border.

On Monday afternoon, police found a white Volkswagen minivan that the suspect was believed to be driving. They did not elaborate on its condition or say if anything else was found in it.

Police also published several photos of the man, the latest of which they said was taken shortly before his attack on the CSS insurance office.

It shows a tall, balding man with short brown hair walking along a street in a green jacket carrying a large black bag, which they said may have contained the chainsaw.