At sunrise one day last spring, the leaders of the Connecticut tribes that own two of the world's largest casinos stood together at the site of a 1637 massacre, commemorating the Pequot War attack in which one of their tribes took part in nearly wiping out the other.

The Mashantucket Pequots, who own the Foxwoods Resort Casino, hold the event annually to celebrate survival from the slaughter of so many of their forebears. Last year was the first time they invited a member of the Mohegan Tribe, which owns the Mohegan Sun casino, to participate in the fireside ceremony in Mystic, Conn.

"That was pretty big," Mohegan Chairman Bruce "Two Dogs" Bozsum said in an interview last month with The Associated Press.

The commemoration was a symbolic moment in the close relationship between the two chairmen. With their rival casinos each struggling through slumps, the men see each other not only as friends, but also as allies in a relationship that may be a key to their tribes' future prosperity.

Although the tribes once kept their external affairs entirely separate, Bozsum and the Pequots' chairman, Rodney Butler, have sought to speak in a single voice on issues of mutual interest. In joint talks with Connecticut's governor, they have won concessions including a reduction in the presence of state police at the casinos to lower the amount they have to reimburse the state.

They are also exploring the possibility buying goods and services together to reduce costs for their massive casinos, which are only seven miles apart in rural southeastern Connecticut.

"It was only good fortune, or good misfortune, that both of us were going through the same economic challenges at the same time," Butler said in a separate interview this month. "How much more successful can we be simply working together?"

Bozsum, 52, first met Butler years ago when he would play golf with Butler's father, but they became close in recent years after each was elected chairman. The friendship has influenced relationships between the tribes, which hold intertribal socials more than ever. Bozsum and Butler, 35, are golfing partners, their families have socialized together, and they speak frequently over the phone.

When talk turns to business, they have plenty of shared challenges to discuss.

Foxwoods and Mohegan Sun opened after the Pequots won federal recognition in 1983 and the Mohegans followed in 1994. After years of success, they have struggled with a steady decline in gambling revenue brought on by the economic downturn and new competition in neighboring states.

The Mohegan Tribal Gaming Authority, which owns casinos in Uncasville and Wilkes-Barre, Pa., announced in March it had refinanced debt of about $1 billion, and the Pequots said in October that creditors had signed on to its plan to restructure $2.2 billion in debt.

Bozsum said the two men discuss industry trends and joke together about their marketing and other strategies, but they do not share proprietary information.

"We do our own thing, but we watch each other. And we both probably adjust to what's happening across the street," Bozsum said.