A 37-year-old Germantown man died of gunshot wounds early yesterday after being shot during an argument with an off-duty Montgomery County police officer outside a hotel south of Gaithersburg, county police said.

George Peter Valltos of the 19000 block of Frederick Road died at about 4 a.m. at Suburban Hospital in Bethesda, said police spokesman George Ludington.

Authorities said Valltos was shot twice in the chest Saturday night by Officer Harold K. Allen, who was working as a hotel security guard. The shooting occurred in a parking lot at the Sheraton Potomac Inn off I-270 near Shady Grove Road.

Allen, 28, who has been on the force for three years, was not injured, Ludington said.

Valltos had been in the hotel lounge with friends at about 10 p.m., police said. Valltos became disorderly, Ludington said, and Allen told him to leave the hotel.

A short time later, police said, Valltos returned. He became disruptive and was accompanied by Allen to the hotel's parking lot. Ludington said Allen was attacked by Valltos and a struggle ensued.

At one point, Ludington said, Valltos picked up a 12-inch metal flashlight belonging to Allen that had fallen to the ground during the clash. The man attacked Allen with the flashlight, Ludington said, and Allen fired two shots from his .38-caliber revolver, hitting Valltos twice.

County police have begun an investigation of the incident, Ludington said. The county has a longstanding policy of allowing police officers to work as part-time security guards with previous approval, Ludington said. Allen had received approval for the part-time off-duty work, he said.

Police said Allen identified himself to Valltos as a police officer before the scuffle in the parking lot.

A spokeswoman at Suburban Hospital said Valltos died from a bullet wound in the chest. An autopsy is to be completed this week by the state medical examiner's office in Baltimore, authorities said.

Valltos' residence was in the Middlebrook Mobile Home Park, a 200-unit development north of Gaithersburg.

Hotel manager William Gibbs said that Valltos was not a regular patron of the Sheraton. He declined to say how long Allen had been employed by the hotel.