Sources at both LA-based Maguire Properties and Chicago-based Equity Office Corp. confirmed late Monday that Equity Office--the nation's biggest owner of commercial office property--has agreed to pay about $28 million for a 6.5-acre parcel inside Playa Vista.

The controversial Playa Vista project, which covers nearly 1,100 acres in the pricey Marina area of West LA, would be the largest infill project in LA County history. It has been in the works for more than two decades, but has been stalled over the past several years by opponents who say the development will kill-off several species of endangered birds and other wildlife that depend on the area's wetlands for their lives.

"I can't speak for the birds, but this is a tremendous opportunity" for both Equity Office and Maguire Properties, a source familiar with the transaction tells GlobeSt.com.

Equity Office plans to use the land for a project tentatively called Fountain Park Office Center. According to one source, the project would stand near the intersection of Jefferson and Culver boulevards, bordering Culver City.

Last spring, some of the owners of Playa Capital Corp., which claims control of Playa Vista, hired LA-based Cushman Realty to find a buyer for the parcel that Equity Office wants to buy. Soon after, Maguire Partners took the decision to arbitration. Insiders tell GlobeSt.com that Equity Office probably won't break ground on its proposed project until all ownership issues are resolved.