NEW YORK - After months of negotiation, the Seneca Nation of Indians and New York state have signed an agreement to open casinos on Indian land in Buffalo and Niagara Falls.

The plan must still overcome legal challenges and be approved by the federal Bureau of Indian Affairs.

But with the recent signing of a 14-year compact that is estimated to bring several billion dollars in revenue to the Seneca Nation and hundreds of millions of dollars to the state over the life of the agreement, the two casinos came one step closer to reality.

In an effort to offset the economic losses the state has suffered since Sept. 11, legislators who had been reluctant to pursue gambling as a source of revenue moved ahead last fall, paving the way for Gov. George E. Pataki to negotiate compacts for six Indian-owned casinos, three in western New York and three in the Catskills.

"The sun is shining on Niagara Falls and western New York today," Pataki said at a recent news conference in Niagara Falls. "We will have casinos, economic opportunities, development and jobs, jobs, jobs."

The Seneca Nation, which has three reservations in western New York and 6,700 members, voted in favor of the casinos in May. But a sticking point over a labor contract that would cover casino construction workers and employees had held up the agreement.

"It took a long time working this out," said Cyrus M. Schindler, the nation's president, who joined Pataki at the news conference. "We both had a job to do. It's not something that you just run in and sign, like buying a car."

The state stands to earn $300 million to $400 million a year from the two Seneca casinos and the four others that are planned, officials said. If the Seneca plan is approved by the Bureau of Indian Affairs, the first casino will open in Niagara Falls, officials said, in late 2002 or early 2003, followed by the Buffalo casino.

New York state law bars the operation of slot machines or other casino games on non-Indian land except for special charity events like Las Vegas nights.