The World Trade Center site developer said Tuesday he would agree, with conditions, to let the government oversee construction of the 1,776-foot Freedom Tower and a second skyscraper planned for ground zero.

Larry Silverstein, who holds the lease to millions of square feet of destroyed office space, said he would accept economic terms of the government's latest offer, which would have him build and lease three other towers on the site by 2011.

But he asked for several conditions, including that the site's owner immediately approve the deal. The Port Authority of New York and New Jersey has a board meeting Wednesday but had proposed waiting until September for final approval.

Janno Lieber, a Silverstein vice president, said Tuesday that work could begin "immediately" if the deal goes through.

Silverstein said that any remaining issues could be resolved "within a matter of days."

"This is about moving the rebuilding forward as quickly as possible in order to revitalize the city's historic downtown," Silverstein wrote top Port Authority executives. The letter said the two sides would still have to work out "logistical issues" with the construction schedule of Freedom Tower.

Port Authority officials did not immediately respond to a request for comment Tuesday.

Silverstein, who signed a 99-year lease to the twin towers six weeks before they collapsed in 2001, said he would agree to pay an additional $1.75 billion in rent in exchange for promises to fill more than 1 million square feet of office space at ground zero with federal, state and city leases.

Talks broke down in mid-March when the Port Authority walked out of negotiations, saying Silverstein had asked for too much. Politicians called the developer greedy and Silverstein accused the government of stalling rebuilding. It then took more than a month of internal negotiations between the city and the states of New York and New Jersey before a new proposal was sent to Silverstein last week.

In recent days, politicians led by Mayor Michael Bloomberg have called on the developer to make a deal immediately, saying he has let the rebuilding stalemate drag on long enough.