More than 100 Swiss police officers are hunting an alleged chainsaw attacker who injured five people at the offices of a health insurance company on Monday morning.

Officials in Schaffhausen, a mid-sized town near the German border, are searching for Franz Wrousis, a 51-year-old whom they described as an aggressive man who mainly lives in the woods.

Police believe he attacked the offices of CSS, a Swiss health insurer, this morning, leaving two people severely hurt and three others with minor injuries. It was not terror-related.

They issued photographs of Wrousis apparently dated from last month, showing him surrounded by trees.

Police described Wrousis as being 6 feet 2 inches tall and having a "scruffy appearance." They also said he had shaved his hair since the photographs were taken and is now bald.

Schauffhausen Swiss chainsaw attack scene

Foto: Armed police stand guard at the scene of the attack in central Schaffhausen. source Reuters

Officers at a press conference said Wrousis is "aggressive, dangerous, and mentally conspicuous" and has twice been convicted of weapons offences. They believe he has been living in the wilds since moving out of his home in Grisons, a canton in the east of Switzerland.

Officers said Wrousis was driving a white VW Caddy with a number plate from the canton of Graubünden, which was found abandoned on Monday afternoon.

Schaffhausen locator map

Foto: source Google Maps

A statement issued by the Schaffhausen police department said his attack was directed primarily at the insurance company, but that he could still be a danger to the public.

Here's a translation of the statement:

"[Wrousis] is usually found in the woods, according to our sources. When cornered, he apparently reacts aggressively. As such, it is important that if anyone spots the man, they avoid him and contact the police. Franz W. still has the chainsaw with him, according to our latest information.

"The Schaffhauser police is out in force, due to the circumstances. The search for the armed attacker started immediately. Besides uninformed action forces, the police also stands with civil officials in this mission. The search is running at full strength. The affected property and neighbour houses are searched by police and the residents were evacuated. Additionally, parts of the suburbs and side streets had to be closed off.

"Forces from cantons Zurich and Thurgau are assisting. In total over 100 police officers are in operation. 49 ambulance workers are in operation.

"According to early intelligence, the attack was primarily against the insurance company. However, as the police does not have information about the condition of the attacker, they cannot give the all-clear at the moment. It is not known where Franz W. is at the moment."

An earlier statement dismissed concerns that the attack was linked to terrorism, and said bluntly "this was not an act of terror".

Ambulances and police vehicles gathered in central Schaffhausen immediately after the attack.

Sebastian Kummer, a Swiss software engineer, tweeted a photograph showing the police cordon:

The victims who were injured in the attack are being treated in hospital. CSS said that the two seriously injured victims were its employees, while it could not be sure of the identities of the other three.

In a statement it said it was not immediately aware of any connection between the company and Wrousis.