Gunman shoots 3 people at Phoenix business complex in US

At least three people have been shot and wounded when a gunman opened fire at an office building in the US state of Arizona.

Sergeant Tommy Thompson of the Phoenix Police Department said the shooter arrived at the three-story complex at around 10:30 a.m. local time (1730 GMT) on Wednesday and got into a serious dispute with someone, the Associated Press reported.

Thompson said the argument exacerbated to the point where the man shot the three people, one of them critically.

The victims were taken to a local hospital for treatment.

The gunfire prompted horrified workers throughout the complex to lock the doors to their offices and hide far from the windows.

Several individuals also received treatment for stress-related symptoms.

Phoenix Police Department Sergeant Steve Martos said there is speculation that the assailant was an aged man, who left the office building in a white car.

The incident took place amid growing fears in the United States over mass shootings.

On December 14, 2012, twenty children and six adult victims were fatally shot by a gunman — who later killed himself — at the Sandy Hook Elementary School in the town of Newtown in the US state of Connecticut. Earlier in the day, the assailant killed his mother in another location.

There have been reports that the twenty-year-old killer, Adam Lanza, suffered from a personality disorder, was on the antidepressant Prozac, and was fond of first-person shooter games.

Every year, more than 30,000 people are shot and killed in the US.

The US averages 87 gun deaths each day as a function of gun violence, with an average of 183 injured, according to the University of Chicago Crime Lab and the Centers for Disease Control.

The year 2012 was a record setting year for gun sales in the US.

About 4.5 million firearms are sold annually in the United States at a cost of 2 to 3 billion dollars.