A gunman who police said was about to be fired was holed up Friday at a Reno, NV Walmart store where he worked after three co-workers were shot in a possible retaliation attack, said an AP report.
Heavily armed officers entered the building about four hours after the gunman arrived about 8:30 a.m. and wounded his fellow employees, including a store manager.
The gunman was identified as John Dennis Gillane of Reno, who appeared to have a handgun, the report said.
Police negotiators had established contact with Gillane by telephone and were trying to persuade him to surrender. 
Police had not determined a motive for the attack but suspected it was related to a termination.
One of the victims was critically wounded, but "the prognosis is good for all of them," said Dan Fogleman, a spokesman for Wal-mart Stores Inc.