The D.C. Zoning Commission gave its approval yesterday to the Brookings Institution's controversial design for a $25-million office and condominium complex, including construction of an office building that would tower over three town houses in the 1700 block of P Street NW.

The commission, on a 4-to-1 vote, rejected claims by some residents who live near the proposed complex that the liberal think tank's design violates the commission's 1983 order to provide housing in all areas that front on P Street.

Under the plan approved by the commission, Brookings' new complex, to be built immediately to the west and rear of its Massachusetts Avenue headquarters, would include three three-story town houses built along P Street's sidewalk directly in front of, and partly under, the top five floors of an eight-story office building recessed 16 to 22 feet off P Street.

Brookings had proposed that the town houses be only two stories high. But the commission ordered that the institution add a floor to each of them, on the theory that the extra floor would make the town houses look more like other row houses in the 1700 block of P Street and also further shield the office building.

The Brookings plan also calls for construction of up to 79 condominiums along P Street to the east of the town houses and designing the office building so that workers would have to enter it on Massachusetts Avenue.

Neil H. Cullen, Brookings' director of administration, said he was "generally pleased" with the commission's action, but said, "The question is whether we can add the extra floor to the town houses with the minimum effect on the office windows, which we need."

Cullen has said that Brookings and its developer, the Oliver T. Carr Co., need as many windows in the office building overlooking P Street as possible to make the project "economically viable. If you're going to pay Massachusetts Avenue rates, then you want a window."

James McGrath, head of a citizens coalition fighting the proposal, said the group was "amazed and appalled that the commission would in any way consider the town house plan in compliance" with the 1983 order.

One sentence in the earlier order said, "All areas of the building which front on P Street NW shall be devoted to residential use," a condition designed to preserve the character of the 1700 block of P Street, a quiet, mostly residential enclave a block from the congestion of Dupont Circle.

McGrath said the commission had been "bamboozled by the Brookings proposal. The town houses are nothing but Tinker Toy apartment units. Whether they raise them one story or not is immaterial."

Commission member John G. Parsons, a National Park Service official, agreed with McGrath, saying, "I cannot see how any of us can say this is residential along P Street."

But his four colleagues -- Architect of the Capitol George M. White, commission Chairwoman Maybelle T. Bennett, and Commissioners Lindsley Williams and Patricia N. Mathews -- voiced support for the Brookings design, with Bennett's statement and proxy vote read aloud at the meeting.

"If the fronting along P Street is residential and people can't get to the offices from the P Street side , it seems to me it's residential," White said.

The commission's approval was tantamount to a final decision on the Brookings plan. The National Capital Planning Commission will now review the proposal, but cannot reject it, only make recommendations to the commission, which then will schedule one more vote on it.

Cullen said construction could start late this year or early next year, after final design changes are made to comply with the commission's ruling.