City and state officials, in a memorandum they never released, promised the developer Forest City Ratner six months ago that they would arrange for the firm to obtain the rights to build almost 1.9 million square feet of residential and commercial space in downtown Brooklyn, even if the Metropolitan Transportation Authority rejected the firm’s bid for the development rights at a nearby rail yard.

The disclosure of the February 18 memorandum comes three weeks after the MTA board told Forest City Ratner the firm’s $50 million cash bid was insufficient. The firm’s president, Bruce Ratner, is also the principal owner of the New Jersey Nets, and he is seeking to build an arena at the rail yard to house his professional basketball team.

A rival firm, Extell Development Company, offered the MTA $150 million for the development rights at the rail yard, but the transportation authority’s board, which is dominated by members appointed by Governor Pataki and Mayor Bloomberg, voted July 27 to negotiate exclusively with Forest City Ratner.

Council Member Letitia James, who has led the opposition to the Ratner project and whose district includes the rail yard, said the memorandum speaks volumes about the cozy relationship that Mr. Ratner maintains with city and state officials.

“It says that he is a favored developer, and it says to me that he’s going to continue to have a monopoly on downtown Brooklyn and in my district without giving any other developer the opportunity to bid,” she said.

In early March, Messrs. Bloomberg and Pataki announced a separate memorandum, also signed on February 18, endorsing Mr. Ratner’s plans to build a 7.8 million-square-foot commercial and residential complex in downtown Brooklyn. The high-rise development would encompass the 8.4-acre MTA-owned rail yard, as well as nearly 13 additional acres in the adjacent Prospect Heights neighborhood. Mr. Ratner’s firm has purchased most of the Prospect Heights property, but a handful of homes and small businesses face seizure by city and state officials through eminent domain to make room for the developer’s ambitions.

Although Messrs. Bloomberg and Pataki announced one of the two February 18 memorandums with considerable fanfare, they did not mention the other, which was signed by Mr. Ratner and by the deputy mayor for economic development, Daniel Doctoroff; the Pataki administration’s chairman of the Empire State Development Corporation, Charles Gargano, and the Bloomberg administration’s president of the Economic Development Corporation, Andrew Alper.

In it, the officials agreed to facilitate Mr. Ratner’s development aspirations at a pair of nearby properties along Atlantic and Flatbush avenues: a Ratner owned mall located north of the rail yard, Atlantic Center, and a commercial block on Flatbush Avenue, which is referred to as Site 5 in the memo. That site is currently occupied by a sporting goods retailer, Modell’s, and an electronics store, P.C. Richard & Son.

The development called for in that memorandum increases by 25% the square footage that Mr. Ratner – whose previously publicized project has been attacked in some quarters as too big – would construct in the area.

A Ratner spokesman, Joseph DePlasco, said yesterday, “The proposed development at Site 5 should not come as a surprise to anyone.” He noted that the firm’s plans for the site were revealed in many public meetings, including a presentation at a May 26 hearing of the City Council. Also, a chain of local weeklies, the Brooklyn Papers, reported that a vice president of Forest City Ratner, James Stuckey, mentioned plans for Site 5 at the May 26 hearing.

Another council member from Brooklyn who opposes the Ratner project, Charles Barron, said yesterday, however, that although he attended the May 26 hearing, he was never informed about plans to build an additional 1.9 million square feet at Atlantic Center and Site 5. After The New York Sun contacted Mr. Barron to ask about his reaction to the newly surfaced memorandum, the council member said: “This is the first time I’ve heard of it.”

Council Member James, too, said she had no recollection that plans for Atlantic Center and Site 5 were mentioned at the May hearing. As for the memorandum, a spokeswoman for the Economic Development Corporation, Janel Patterson, said that although it was never distributed publicly, it “has been available to anyone that requested it.”

The anti-Ratner group Develop Don’t Destroy obtained a copy of the previously unreleased memorandum and distributed it to reporters yesterday. A spokesman for the group, Daniel Goldstein, would not say how he initially secured a copy of the memo. But he said that, given the failure by city and state officials to disclose the existence of the memo before yesterday, “Why should we trust any of the information the public has seen from the developer and the public agencies?”

Forest City Ratner has said that the 21-acre Atlantic Yards project – which does not include the Atlantic Center and Site 5 developments – will create 7,500 permanent jobs as well as 2,250 units of affordable housing.

Mr. DePlasco, the Ratner spokesman, said that the firm “already owns part of what is being called Site 5 here,” but that P.C. Richard, which also owns part of the site, has not yet agreed to sell its stake. He said negotiations between Forest City Ratner and P.C. Richard are continuing.

In the newly surfaced memorandum, state and city officials said they would aid Forest City Ratner’s efforts to gain control over the remainder of Site 5, specifically mentioning the possibility that they will use eminent domain.

Regardless of whether Mr. Ratner’s arena plan comes to fruition, the memorandum authorizes his firm to build 308,000 square feet of residential space at Site 5 and 1.3 million square feet of commercial and residential space at Atlantic Center, “subject to obtaining necessary approvals.” Under the terms of the memo, Mr. Ratner’s firm will build an additional 328,000 square feet of office space at the Atlantic Center site if his bid for the MTA site falls through.

The famed architect Frank Gehry, who was hired by Mr. Ratner to design the proposed high-rise hub,has sketched plans for a 60-story tower along Flatbush Avenue that would be named “Miss Brooklyn.” If the MTA approves the Ratner bid, allowing the Miss Brooklyn plans to proceed, then, according to the newly surfaced memorandum, the developer will be able to transfer the additional 328,000 square feet of zoning rights from Atlantic Center to Site 5.