ZUG, Switzerland (AP) _ A Swiss man in an orange police vest sprayed assault rifle fire and set off an explosive during a session of a state parliament Thursday, killing 13 people before turning the gun on himself, officials said.
Sixteen others were injured, including eight lawmakers and the head of the Zug canton's government, Hanspeter User, who was seriously hurt, police said. Three government officials were among the dead.
The man _ who apparently had a grievance against local officials _ stormed into a morning joint session of the state government and parliament, opening fire with the rifle. He then detonated an explosive device, said Zug police chief Urs Hurlimann. He was wearing a bright orange police vest.
As lawmakers hit the floor in panic and the injured screamed in pain, journalists who were covering the parliamentary meeting cowered behind their desks for cover.
``The man strode through the whole floor, shooting at people,'' Swiss Telegraphic Agency reporter Dominik Hertach told Swiss television.
There was then an explosion, he said, and smoke filled the room. The force of the blast ripped doors off and shattered windows of the stately building near Zug's quaint old town and glistening lake.
The gunman used a 5.6 mm SIG ``Sturmgewehr 90,'' the Swiss-made assault rifle commonly used by the country's militia army, police said. It was not clear, however, if he was a soldier or policeman.
Three members of the government were among the dead, Peter Hess, president of the Swiss national parliament in Bern, told lawmakers who suspended the session in shock. Hess is from Zug.
Hurlimann said eight lawmakers were seriously injured. He would not give details on identities of the victims or their role in government or parliament.
The chamber was packed at the time with 80 local lawmakers and seven government members, as well as journalists.
The man, who lived in nearby Zurich, left a letter behind in which he spoke of a ``day of rage against the Zug Mafia.''
``On the basis of this letter, we can exclude any type of connection with the terrorist attacks in the United States,'' Hurlimann said, adding that the cause seemed to be a grievance against local authorities.
Zug is a wealthy, lakeside town near Zurich, best known within Switzerland for its low tax rate. Zug is also the name of the canton and its state legislature has widespread powers over issues ranging from education to taxation and health care.
Radio reports said a car with Swiss license plates _ and containing a cache of weapons _ was seized by police.
Viktor Schaech, who runs a kiosk near the parliament building, said he was chatting to a friend when he heard the sound of shooting.
``It was complete chaos,'' he said. ``It was absolutely awful. I'm still in shock.''
The attack _ the worst on record in Switzerland _ shattered the morning tranquility.
Switzerland has among the most liberal gun laws in the world. Men who serve in the nation's militia army all keep their weapons at home. Despite this, violent crime is rare and there are only minimal controls at public buildings. Politicians rarely have police protection.
Swiss parliament president Hess said security might now have to be reviewed.
``We want to keep an open house and let visitors in,'' Hess told journalists. ``But maybe now we have to look at tighter restrictions.''