Geneva: A letter bomb has exploded at an office of the Swiss nuclear power industry in the northern city of Olten, injuring two people, police said on Thursday.
The explosion happened shortly after 8 am (0600GMT) as staff were opening the morning`s post in the fourth-floor office of Swissnuclear, said police spokeswoman Thalia Schweizer.
Swissnuclear is a lobby group representing national power companies Axpo, Alpiq and BKW.
Schweizer said the two staff members had been taken to a hospital but their injuries appeared to be superficial.
Opponents of nuclear power in Switzerland have become more vocal in recent weeks as images of the stricken Fukushima reactor in Japan appear on the evening news bulletins daily.
Switzerland has five nuclear reactors currently in operation.