WASHINGTON: One person was killed and four others wounded Tuesday when a man who was unhappy with the treatment he had received at a Minnesota health clinic opened fire inside the facility, authorities and US media said.

Police arrested the suspected shooter, identified as Gregory Ulrich, 67, who was known to law enforcement from previous encounters. He allegedly went into the Allina Health Clinic in Buffalo, Minnesota just before 11:00 am (1700 GMT) and opened fire.