A gunman opened fire in the lobby of a California hospital killing one person and wounding another before turning the gun on himself, police said.

The incident happened Thursday morning at the Long Beach Memorial Medical Center about 40 kilometers south of Los Angeles.

The shooter and the victims all worked at the hospital, Long Beach Memorial CEO Diana Hendel said at a press conference.

"Today it's with a heavy heart that I announce that we lost two members of our employee family, and a third is in critical condition," Hendel said.

According to local television channel KCAL9, the gunman, who worked at the hospital pharmacy, had recently received his dismissal notice. The victims reportedly worked with him.

Long Beach Police Chief Anthony Batts said that his officers have not yet established a motive.

However, shootings like this are "becoming a national trend, probably because of the tension that's going in our society today," he said, referring to a series of serial shootings over the past months and the US economic downturn.

Earlier this month a man in Washington state shot dead his wife, daughter and two other people before killing himself.

Days before that a recently unemployed man stormed an immigrant services center where he had been learning English in Binghamton, New York and went on a rampage, killing 13 people before taking his own life.

On 29 March, a heavily armed gunman shot dead eight people at a North Carolina nursing home, days after six people were killed in a murder-suicide in an upscale neighborhood in northern California's Silicon Valley.

And on 10 March, an unemployed man killed his mother, grandmother and eight others on a vicious shooting rampage in Alabama.