ST. REGIS INDIAN RESERVATION, N.Y. (AP) _ State police warned gamblers to stay away Saturday night as Indian casinos reopened for the first time since gambling opponents blockaded this strife- torn Mohawk reservation in March.

Fearing further violence after nearly a week of nightly gunfire and vandalism, more than 500 women, children and elderly people fled Friday from the Canadian side of the St. Regis Mohawk Reservation. The reservation, home to some 14,000, straddles the U.S.-Canada border.

The reservation was quiet Friday and Saturday, authorities said.

Authorities and Mohawks had feared renewed violence when workers returned home for the weekend and casinos reopened. Although some casinos were open, many of their employees stayed home and the usual busloads of customers were expected to be absent Saturday night.

State police put up informational roadblocks at entrances to the Mohawk land, warning people to stay off the reservation because of violence. Customs agents along the border searched cars for weapons.

Residents are divided over casinos and bingo halls on the American side of the reservation.

The feud also touches on the question of Indian sovereignty - whether state and federal officials have the authority to intervene in a dispute between Indian factions.

In late March, gambling opponents blockaded roads leading to the reservation. Pro-gambling Mohawks tore down the blockades in a fierce fight Tuesday night, and for several nights there were violent confrontations between the factions.

Buildings on the reservation are spray-painted with pro- and anti-gambling slogans, and areas where fighting has occurred are littered with broken glass, burnt car parts and spent shells.

Mike Mitchell, chief of the Canadian Mohawk Council, said he ordered the evacuation because residents were in danger. Evacuees were housed in dormitory rooms at a training center for air traffic controllers in Cornwall, Ontario.

Evacuees decided to return home Monday if they don't get a commitment of support from the American or Canadian governments, Mitchell said.

He said he believed both sides in the gambling dispute should surrender their arms, but he doesn't think that will happen voluntarily.

''If no outside government gives us assistance putting those weapons away, we're going to have to do it ourselves,'' he said.

Mohawk Chief Harold Tarbell, a gambling opponent, has called on New York Gov. Mario Cuomo to send in the National Guard to restore order.

Cuomo said Saturday that ''so far there is no necessity for military involvement.'' He said some Mohawks were exaggerating the seriousness of the violence ''to advance their own political cause.''

One Mohawk chief, David Jacobs, agreed that some Indians were making the violence sound worse than it was.

''It is my profound hope that Chief Tarbell's alarmist calls for intervention do not result in the revival of unrest on the reservation,'' said Jacobs, a gambling supporter.