Governor Pataki and Mayor Bloomberg met with the World Trade Center leaseholder, Larry Silverstein, yesterday afternoon and the three agreed to have the Freedom Tower redesigned to address security concerns raised by the New York Police Department.

The redesign will delay completion of the 1,776-foot-tall tower by up to one year, to 2010, officials said.

The meeting, held at Mr. Pataki’s Manhattan office, was also attended by the police commissioner, Raymond Kelly; the outgoing head of the Lower Manhattan Development Corporation, Kevin Rampe, and officials of the Port Authority of New York and New Jersey.

The discussion of security concerns voiced by the Police Department came to a head after a police memo was issued last month detailing potential risks. While the memo has not been released to the public, officials said one concern is the tower’s vulnerability to truck or car bombings because of its placement only 25 feet from West and Vesey streets.

The Freedom Tower will “require a significant redesign, including minor adjustments to location,” Deputy Mayor Daniel Doctoroff told The New York Sun. There will also be changes to “materials and structure,” he said.

Mr. Doctoroff said the cost of the security improvements has yet to be assessed, but he said it was “reasonable to assume that there will be some cost increases.” It is not yet clear how Mr. Silverstein’s added expenses would be covered, Mr. Doctoroff said.

“We believe that a building that meets the NYPD standards can be built consistent with Daniel Libeskind’s Master Site Plan,” Mr. Pataki said in a statement. “Larry Silverstein’s team will continue to work with the NYPD over the course of the next several weeks.”

Mr. Libeskind’s master plan will not change, but it is the architect David Childs who will oversee the redesign.

“While the shape and details of buildings may change, the intent, spirit, and direction of the master plan will remain intact,” Mr. Libeskind said in a statement.

The redesigned Freedom Tower will still have roughly 2.6 million square feet of office space, Mr. Doctoroff said. Critics of the plan have complained that Mr. Silverstein has yet to find an anchor tenant for his 7 World Trade Center, which has 1.7 million square feet of office space, and that with vacancy rates in Lower Manhattan still high, the amount of office space at the Freedom Tower should be reduced.

“Today’s meeting with Governor Pataki and Mayor Bloomberg was extremely productive,” Mr. Silverstein said in a statement. “I am confident that we have a process in place that will allow us to cooperatively address the challenges that lie ahead.”

A number of civic groups and political analysts said they were not surprised by the announcement to redesign the Freedom Tower, but some politicians came out swinging, chiding the mayor and the governor for further delays in a project that is already months behind schedule.

Assembly Speaker Sheldon Silver, a Democrat who represents Lower Manhattan, said: “It is both troubling and unfortunate that it has taken mounting public pressure, the result of months of inaction and delay by Governor Pataki and Mayor Bloomberg, for them to get together and announce that the Freedom Tower needs to be redesigned.”

One of the four Democrats seeking the mayoral nomination, Rep. Anthony Weiner of Queens, called the rebuilding effort “deeply flawed” and said Mr. Bloomberg may have overlooked a year’s worth of warnings from the police department “because of his single-minded focus on the West Side stadium.”

Earlier this week, Mr. Bloomberg told reporters Mr. Silverstein could not be blamed for delays.

“Remember, Larry Silverstein has just built a big building, 7 World Trade Center, which has been topped off, and I think will be a very successful building for him,” the mayor said.

He added that Mr. Silverstein is asking above-market-rate rents and implied that a completed Freedom Tower would compete with signing tenants to his other development.

Officials said last night that the delay in starting construction on the Freedom Tower will not affect plans for a new performing arts center, the World Trade Center memorial, or the new PATH commuter train station, set for 2009.