A gunman brandishing what appeared to be a submachine gun yesterday forced two employes of an Alexandria supermarket into the store lavatory, where they remained for more than two hours until police, fearing they were being held as hostages, stormed the building, authorities reported.

Joe Hart and Will Westcott, employes of the Food Barn at 221 West Glebe Rd., were found huddled in the store lavatory by a police SWAT team about 12:30 p.m. Both employes were "shaken up" but were uninjured and had not been physically assaulted, Police Chief Charles T. Strobel said in a statement at the scene.

No injuries were reported to any of the 80 customers and employes who were in the store when the gunman entered about 9:50 a.m. The robber, who took an undisclosed amount of cash, apparently fled within minutes after the holdup.

After the two employes were found unharmed, about two dozen police officers maintained a cordon around the store for two more hours, fearing that a second gunman might still be inside. A second man was never found, and police last night remained uncertain whether a second person had participated in the robbery, Strobel said.

"We have conflicting reports from witnesses in the store about whether there were one or two," gunmen, Strobel said.

At least one man, described as appearing to be in his mid-20s and armed with a handgun and an automatic weapon, forced Hart and Westcott into the lavatory at the rear of the supermarket shortly after entering the store, Cpl. P. Crawford said.

The gunman, who declared that a second man had accompanied him, then ordered the store's manager to bring him the morning's receipts. After the robber got the money, he was last seen running through an alley beside the store, Crawford said.

Police, however, believed that Hart and Westcott might be held hostages inside the evacuated store. "We still had to assume the worst -- that the two of them were inside with a gunman," Strobel said.

No arrests had been made in the incident as of late last night, Crawford said.