NEW YORK, NY (NBC) -  Two people are dead and nine more are wounded after an early morning shooting outside of New York City's Empire State Building.

Witnesses describe mass chaos as shots rang out in one of the busiest parts of midtown Manhattan.

Police say a lone gunman, identified as 53-year-old Jeffrey Johnson, confronted a former coworker on the street, shot him three times, and walked calmly from the area as the man lay dying on the street.

A construction worker followed Johnson and alerted police.

"As the two officers approached Johnson, he pulled a 45 caliber pistol from his bag and fired on the officers who returned fire, killing him. An additional nine individuals were either wounded or grazed during the exchange," New York Police Commissioner Ray Kelly confirmed in a later news conference.

Two women and seven men were hit by gunfire.

New York Mayor Michael Bloomberg says it's possible those victims were shot by police as they tried to stop Johnson.

Investigators say Johnson was fired from his job in a nearby building last year, but had an ongoing feud with a former colleague which ended in Friday's killing.

"It's a terrible thing, our first thoughts are for the murder victim and then prayers that thank God nobody else was seriously injured and that they will all recover and once again there's an awful lot of guns out there," Mayor Bloomberg said.

Bloomberg expects that all nine wounded bystanders will make a full recovery.

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