New York ? Sixty- to 70-story office buildings, stores, cultural centers and a memorial to the dead are included in six alternative proposals for the World Trade Center site that will be released today.

Officials familiar with the proposals said that all six would replace the 11 million square feet of office and retail space lost in the Sept. 11 attack with a cluster of buildings much shorter than the 110-story twin towers.

The officials, who spoke on condition of anonymity, also said that each version includes a substantial memorial to the victims. But they said only four of the plans set aside the “footprint” of the towers for a memorial a key demand of many victims’ families.

The six plans are rough drafts, not detailed architectural renderings, and represent the first in what could be a contentious series of steps to redevelop the 16-acre site. A final design is set to be selected in December.

“This is the starting point for dialogue,” said Matthew Higgins, spokesman for the Lower Manhattan Development Corp., the city-state agency charged with redeveloping the site. “The next step is to actively engage the public through as many different forums as possible.”

Although only a few developers, planners and government officials have seen the plans, they have already stirred some response.

Mayor Michael Bloomberg called them “a start.”

“I’ve got my own ideas, which I will certainly write to them,” said Bloomberg, who encouraged others to do the same.

While some victims’ relatives initially called for the entire site to be set aside as a memorial, many now say they will be satisfied with a memorial covering several acres, including the footprint of the towers.

“Where Tower 1 and Tower 2 stood is sacred ground,” said Joseph Maurer, a retired firefighter whose daughter, Jill Campbell, died in the trade center. “It’s the same as Gettysburg or Pearl Harbor.”

One official said the proposals also include space for cultural uses, such as theaters and museums. These preliminary plans do not specify particular tenants, but there has been speculation already that the Museum of the City of New York and the New York City Opera could find new homes at the site.

While none of the plans calls for housing on the 16-acre tract itself, they do suggest that damaged office buildings along the periphery be razed for housing or converted to apartments. Several large office buildings near the trade center were so damaged that they remain vacant.

The proposals are to be released by the development corporation and the Port Authority of New York and New Jersey, which owns the land. They will be on public display for several weeks and posted on the development corporation’s Web site.

An expected 5,000 people will discuss the plans at a meeting on Saturday.

The development corporation and the Port Authority will narrow the six land-use proposals down to three by September and then down to one by the end of the year.