NEW YORK (CNN) - Architect Daniel Libeskind, the master plan architect for rebuilding the World Trade Center site, will share authority over a skyscraper that will be a centerpiece of the site with architects hired by developer Larry Silverstein, the trade center leaseholder.

Studio Daniel Libeskind will now collaborate with a team of architects from the firm Skidmore Owings Merrill, led by David Childs, who designed a 52-story office tower for SIlverstein that alreay is being built on the northern edge of the 16-acre site.

The Lower Manhattan Development Corp., which is overseeing this process, announced the agreement early Wednesday after a marathon meeting between Libeskind and Silverstein, who have been jockeying for control over the project.

Though he hasn't designed many buildings, Libeskind won a public, international design competition in February, beating out half a dozen prominent rivals, including SOM.

Libeksind's scheme was considered to have the best setting for a memorial to nearly 2,800 people killed in the Sept. 11, 2001 terrorist attack that brought down the 110-story twin towers and five other buildings.

But the LMDC now says SOM will be "leading a team that will design" Libeskind's main skyscraper -- what is supposed to be a 1,776-foot tower with 70-floors of occupied space for offices, a sky restaurant, and an observatory, capped by a spire that will house a broadcast antenna.

The building would be the world's tallest with a height symbolic of the year of American independence.

Gov. George Pataki, who controls the LMDC with the Mayor of New York, and controls the site owner, the Port Authority of New York and New Jersey, with the governor of New Jersey, has established a timetable for rebuilding that calls for groundbreaking on the Libeskind tower, which he dubs the Freedom Tower, by next summer, topping out in 2006, and ready for occupancy in 2008.

"This collaboration will facilitate the development of the Freedom Tower in a manner consistent with the Libeskind vision," the LMDC said.

Libeskind will remain involved during the "concept and schematic design phases," according to the LMDC.

"We are confident that SOM and SDL will produce a world class icon in the Lower Manhattan skyline and a powerful symbol of our nation's resilience in the aftermath of tragedy," the LMDC said.

What the LMDC did not say is how this sharing of authority over the tower will alter the overall plan, which includes a train station, a performing arts center, and a commemorative museum, in addition to the 4.7 acre memorial below street level in the southwest portion of the site.

Libeskind, a Polish-born son of Holocaust survivors who emigrated to the U.S. and became an American citizen, is best known for designing the Jewish museum in Berlin that opened two years ago.

He has also designed the Imperial War Museum in England and the expansion of the Denver Art Museum, under construction.

Silverstein, a Manhattan real estate developer, signed a 99-year lease on the trade center only six weeks before it was destroyed and is embroiled in litigation to collect as much as $7 billion in insurance proceeds that he says he would devote toward rebuilding.

Silverstein wants to replace all 10 million square feet of lost commercial space with five new buildings over the next decade.

The Freedom Tower would have two million square feet.

Silverstein's 1.7 million-square-foot officer tower adjacent to the site, designed by SOM and Childs, is due to be completed in two-and-a-half years, where 7 World Trade Center, originally developed by Silverstein, previously stood.

Current projects for SOM, designer of Chicago's Sears Tower, which eclipsed the Trade Center as the world's tallest building in the 1970s, include a revamped Penn Station in midtown Manhattan and the new headquarters for AOL Time Warner (AOL: Research, Estimates), the parent company of CNN and CNN/Money.