A developer is taking the first steps to get approval for what he says would be the tallest skyscraper in America on a Philadelphia site.

The proposed American Commerce Center, by a development partnership that includes Walnut Street Capital, would have office space, hotel rooms and retail and entertainment facilities. City Councilman Darrell Clarke introduced legislation Thursday for zoning changes that would be needed.

At 1,500 feet, the Commerce Center would top the 1,451-foot Sears Tower in Chicago. The Sears Tower is the tallest building in the United States and the fifth tallest in the world.

State Sen. Vincent Fumo says he opposes what he calls "spot zoning" for the project. Fumo considers the proposed tower out of scale with the rest of the city. Neighbors say it may block the sun and bring too much traffic.

With the council starting a three-month summer break Friday, the proposal can't be acted on until September.