Rival gangs of Vietnamese refugees were at the center of two violent melees in Arlington within the last two weeks, county police said yesterday. Earlier police had said it was not clear whether the fights were the result of organized groups.

The most recent incident occurred Saturday night when police arrested four men near the Clarendon Metro Station and charged them with carrying concealed weapons. Seized in the incident was a loaded .25-caliber automatic revolver, an unloaded .22-caliber magnum derringer and bullets for the derringer, Bell said. A week earlier a melee between two groups of Vietnamese in Clarendon resulted in 10 arrests, one stabbing and damage to two cars, police said.

At the root of these incidents is "a long-standing feud between two rival Vietnamese gangs," said Tom Bell, a police spokesman.

"There's a problem because the Vietnamese people are reluctant to talk to police," Bell said. "We're trying to gain their confidence, and let them know we're here to help them . . . . We intend to get this stopped before it gets out of hand," he said.

At about noon Saturday, a fight among six to eight Vietnamese men was reported at the Asia Supermarket in the 6200 block of Wilson Boulevard of Fairfax. The men left before police arrived, and there were no arrests in this incident. Police received reports from witnesses who observed the men fighting with machetes and hatchets, Bell said.

Bell said that police in the area later stopped groups of Vietnamese men and seized a large butcher knife and a machete. No arrests were made.

Saturday night a special police tactical unit staked out the area near the Clarendon Metro Station and arrested four men, charging them with carrying a concealed weapon. The men charged were: Khanh Long Le, 23, of 3036 Patrick Henry Dr., Falls Church; Cam Tan Ngo, 25, of 6200 Leesburg Pike, Falls Church; Quoc Van Vo, 34, of 2917 Peyton Randolph Dr., Falls Church, and Chin Quan-Dun Ha, 20, of 840 South Dickerson St. in Arlington.

Dorothy T. Grotos, member of the Arlington County Board, said that she had heard that there had been problems in the past with gangs. "I hope it doesn't escalate," she said.

Grotos said that she had heard indirectly about small incidents in the county schools.

Ellen Bozman, chairman of the Arlington County Board, said that she had not heard until recently about the possibility of gang warfare in Arlington. She said that she believed that the answer to the problem lies in trying to find the root of the problem, not "chasing it into another jurisdiction."