NEW YORK -- With two years to go before it opens, developer Larry Silverstein has not signed an anchor tenant for the rebuilt 7 World Trade Center and has stepped up his marketing campaign for it, real estate brokers say.

Crain's New York Business reported Monday that negotiations have broken down between Silverstein and the Port Authority of New York and New Jersey, which was widely assumed to be the anchor tenant.

Port Authority spokesman Greg Trevor said he had no comment on the report.

Gerald McKelvey, a spokesman for Silverstein, said the developer is "obviously" seeking tenants for 7 World Trade, scheduled to open at the end of 2005, but he would not comment on negotiations with the Port Authority.

Robert Freedman, vice chairman of GVA Williams, a real estate brokerage, said he attended a luncheon on Silverstein's private yacht this month at which Silverstein urged brokers to promote the building to their clients.

"He's clearly launching an intensive marketing campaign," Freedman said. "He was very positive and uptempo."

Silverstein developed the original 7 World Trade Center, just north of the main trade center site. The building collapsed hours after the destruction of the twin towers, where Silverstein was the leaseholder.

The old 7 World Trade Center housed a Con Edison substation, the mayor's Office of Emergency Management and other government and financial-services offices.

The new 52-story building, designed by David Childs of Skidmore Owings and Merrill, is being financed through insurance payments and Liberty Bonds. The Con Ed station is being rebuilt now, and construction of the tenant floors is due to start in November.

Freedman said the Port Authority could still end up at 7 World Trade even if negotiations have stalled.

"These things have a way of proceeding in fits and starts," he said.

Bruce Surry, an executive vice president at CB Richard Ellis, agreed.

"The Port Authority should still be considered a viable tenant," he said. "I'm pretty confident nothing's fallen through."

M. Myers Mermel, chief executive of the real estate brokerage company TenantWise, said Silverstein needs a government tenant _ either the Port Authority or a federal agency _ or he will have trouble leasing 7 World Trade.

"If that's not possible that may delay his plan to rebuild it," Mermel said.