The looters had been ravaging Olde Towne Mall for more than an hour yesterday before police agent Ron Starr, the only officer within a mile of the renovated East Baltimore shopping center, came face to face with 400 adults and children.

With refrigerators and televisions strapped onto their backs and jewelry stuffed into their pockets, the 400 advanced on the lone officer.

Starr, aware that the closest police reinforcements were trapped in snow, decided to stand his ground. "I pulled my service revolver," he recalled, 24 hours later, "and told them they weren't going to take that stuff out of this mall. I told them I'd fire five rounds into the crowd and I'd save the sixth round for myself.'

The band of looters -- which included entire families working together -- obeyed the command, dropping the stolen goods to the ground of the narrow mall corridor. "For a minute I felt relief," Starr said.

"Then they just returned to the same stores, took more of the same items, and left by a different route around me."

By the time fellow officers arrived an hour later, Olde Towne Mall -- one of Baltimore's urban renewal showcases, a dressed-up shopping center in the middle of poverty -- had been picked clean. "It looked like the locusts hit," Starr said today.

Old Towne Mall was one of the hardest hit sections of Baltimore during a widespread looting spree that began as soon as the record snowfall ended about noon Monday and continued throughout the day and night.

By tonight, Baltimore police, with the aid of 100 state troopers and snow trucks furnished by the National Guard, had arrester 347 persons for breaking and entering and another 366 for violating a 7 p.m. curfew imposed Monday and today by Mayor William Donald Schaefer.

The looting that left commercial sections of Baltimore looking like war zones was especially destructive in Olde Towne Mall, which has become a symbol of this city's rehabilitation efforts more than a decade after it was the starting point of the 1968 citywide riots.

The merchants who helped restore the once-decaying shopping area by sprucing up their own properties and supporting neighborhood programs were back at work today, boarding up broken windows, sweeping up shards of glass.

"This makes you want to turn against your own people," said Bernard McFadden, owner of a women's dress store who grew up in the housing projects of predominantly black East Baltimore. "We're trying to make it and they keep taking us further down. I'm ready to give it up."

For Gerald Jeffein, owner of a large department store, the looting demonstrated the weak foundation of today's society. Walking through the emptied first floor of his store, examining the now-cleared racks of television sets, mink coats and leather jackets, Jeffein said: "There's no morality. There's no morality. It's all you can get away with."

"It was like they declared World War III on us out there," said Officer David Buschman, who spent the afternoon and night attempting to control looters in the Pennsylvania Avenue section of West Baltimore. "The looters were everywhere we turned, and it wasn't easy trying to get at them in that mess.'

Police Chief David Pomerleau and Col. Thomas S. Smith of the State Police said their men were not barred from using weapons if necessary during their antilooting patrols.

"They have my authority to shoot," Smith said. As of late this afternoon, however, there were no reports of serious injuries to policemen or civilians.

Mayor Schaefer, at an afternoon press conference, said he was "disgusted, disappointed and ashamed" of the looters. "I have no sympathy for people who do this," he said. "I have only contempt."

Baltimore officials said the looting in their city was concentrated in the primarily black commercial sectors in West and East Baltimore. According to Sgt. Michael Bass of the police communications unit, there were sporadic reports of looting this morning. He said, however, that most of the breaking and entering occurred between 2 p.m. and 4 p.m. yesterday, when police responded to more than 800 calls.

Although the storm had its most severe aftereffects in Baltimore and Prince George's, other parts of the state were not immune from trouble. In Annapolis itself, local police arrested a small number of looters and spent much of the afternoon trying to control a wild snowball fight that at one point involved about 100 persons.

In Ocean City, Mayor Harry Kelley watched forlornly as an enormous ice flow barged in off the Atlantic Ocean and destroyed some 100 yards of that city's fishing pier.

Over in Annapolis, Gov. Harry Hughes spent the day closeted in his second-floor State House office with his legal counsels, considering what action could be taken to assure that merchants who were struck by the looters could collect small loans and insurance to recover from the vandalism.