Injured expected to survive after man shoots former colleague by Empire State Building

A recently laid-off shop worker has shot dead a former colleague outside New York's iconic Empire State Building before being killed by police.

Nine others were hit by gunfire in the confrontation, but police said all were expected to survive.

The shooting set off chaos in the heart of Manhattan at the height of the tourist season and just after the morning rush hour. Police on their regular anti-terrorism duties rushed to the scene.

Mayor Michael Bloomberg said some of the victims may have been hit by police bullets as police and the gunman exchanged fire.

"This was a terrible tragedy," Mr Bloomberg told a press conference. "We are not immune to the national problem of gun violence."

Police identified the gunman as Jeffrey Johnson, 53, a former designer of women's accessories who was laid off last year. They said they had little details yet about his background, including a criminal record.

Police Commissioner Ray Kelly said Mr Johnson turned his .45-calibre pistol on officers and they returned fire. It is not clear if Johnson opened fire on the officers.

Mr Kelly said Johnson fired at the former colleague three times at close range after a dispute. The name of the 41-year-old victim was not released pending notification of the family.

Federal officials said the 9am local time (2pm Irish) shooting was not related to terrorism.

Construction worker Chris Ogden told the Daily News newspaper he was working on scaffolding above one entrance to the building when he saw someone in a suit and carrying a briefcase start shooting.

"He shot the guy in the head," Mr Ogden said. "The guy went down. He took a second shot when he was down."

Aliyah Imam told Fox 5 News television she was standing at a red light when a woman standing next to her fell to the ground. She said the woman was hit in the hip.

The gunman was "shooting indiscriminately at people", Ms Imam said.

Resident Rebecca Fox, 27, said she saw people running down the street and at first thought it was a celebrity sighting. Then she saw a woman shot in the foot and a man dead on the ground.

"I was scared and shocked and literally shaking," she said.

A body remained at the scene more than an hour after the shooting.

Police scoured the area for bullets.

The Empire State Building is at the heart of one of the city's busiest areas.

About four million people visit the tower's observatory decks each year, and pavements outside the building bustle with people selling tickets for its attractions.

The shooting happened at the junction of 34th street and Fifth Avenue. Streets around the immediate area remained closed.