-- Ground Zero officials defended plans to build a museum on freedom at the site as dozens of victims' relatives launched a nationwide effort calling for its removal from the plans.

New York Gov. George E. Pataki's chief of staff, John Cahill, stressed that rebuilding officials will not allow the museum's mission to be "hijacked from the political right or the political left."

"We were attacked that day because of our values and because of our freedom," Cahill said.

The center would have exhibits on slavery in America, the Holocaust and global human rights issues, but families are worried that some of the exhibits would diminish the sanctity of the adjacent memorial.

Relatives rallied at Ground Zero on Monday as they stepped up their opposition to the center, set to be located in a building next to the Twin Towers' footprints that will be the centerpiece of the memorial slated to open in 2009.

"If you put something like that there, it would be a magnet for protesters," said Charles Wolf, 51, of Manhattan, whose wife, Katherine, died on Sept. 11, 2001.

Relatives are starting a letter-writing campaign to politicians calling for the building housing the International Freedom Center and the less-controversial Drawing Center to be removed from the block housing the Sept. 11 memorial.