The developer Donald Trump is jumping feet first into the fray over ground zero, holding a press conference this morning to unveil a plan to replace the beleaguered Freedom Tower envisioned by the architect Daniel Libeskind with a modern version of the Twin Towers.

Mr. Trump is suggesting a rebuilt Twin Towers rising one story taller than the original buildings. The design was proposed last year by Herbert Belton and Ken Gardner.

“If someone knocked down the Statue of Liberty,” Mr. Trump said in a statement yesterday, “you wouldn’t put the Eiffel Tower in its place. Why are we building this monstrous skeleton known as the Freedom Tower? If Freedom Tower is built, the terrorists win.”

Known as Team Twin Towers, Mr. Gardner, a structural engineer, and Mr. Belton, an architect who worked on the original Twin Towers in the 1960s, released an updated version of Minoru Yamasaki’s 1962 design several months after the release of the Freedom Tower designs.

Yesterday, Governor Pataki, asked by reporters about the Trump plan, indicated it would be nearly impossible for Mr. Trump to get involved in the rebuilding process now.

“Larry Silverstein owns the development rights, the Port Authority owns the land, and we have a public process that has resulted in what I believe is a visionary master site plan that is being implemented intelligently and appropriately,” Mr. Pataki said.

As for whether the governor was annoyed by Mr. Trump’s timing, he said: “This is New York. People do what they want to do.”

According to the plan devised by Messrs. Gardner and Belton, the Twin Towers would be extended to 115 floors and would include modern features to enhance its security, such as a “tube-within-a-tube” design of outer and inner columns.

The planned 1,776-foot Freedom Tower went back to the drawing board last week after the New York Police Department raised security concerns about the plan. A redesign of the Libeskind plan, which is being conducted by another architect, David Childs, is to be released next month.

Meanwhile, planning for another building at ground zero, the Cultural Center, is proceeding. At a press conference tomorrow, the design of the building, which is to house the memorial’s visitors center, the International Freedom Center, and the Drawing Center, is being released to the public.