MEMPHIS, Tenn. (AP) _ A proposed 31-story, pyramid-shaped arena on the banks of the Mississippi River has won the support of two key civic leaders.

The pyramid would house a 17,500-seat sports and entertainment arena and cost at least $49 million.

Memphis Mayor Dick Hackett and Shelby County Mayor Bill Morris said Monday they will ask their local governments to spend $39 million on the project. The rest of the money would come from private investment.

For their money, the investors would get control of the top floors of the structure, Morris said.

Hackett and Morris have given the pyramid proponents until July to provide specific plans and cost estimates. The planning is to be accomplished with $300,000 promised by businessman John Tigrett.

Tentative plans call for building the pyramid on 30 acres of riverside land beside the city's downtown convention center.

For several years, city and county officials have talk about building a sports and entertainment complex.

Officials from Memphis State University have taken part in those discussions. Last month, however, they announced the school is going ahead with plans for building a $39 million arena on campus for basketball games, graduation exercises and other school functions.