The tenants were responding to last week's news that the London-based investment bank Dawnay, Day Group was paying $225 million for the 47 buildings in East Harlem and seven condominium units in the East Village.

Dawnay, Day has no telephone listing in New York. The company is represented here by the Arent Fox LLP law firm, which offered a response to protesters' fears about rents from Dawnay, Day director Iain Blakeley. He said in London that "the company cannot displace tenants nor increase rents above the legal regular increases if they are legitimate tenants in occupation."

The Harlem buildings include more than 1,000 apartments and 55 commercial properties just north of Central Park.

With Manhattan real estate prices skyrocketing, East Harlem has been a last refuge for many people seeking affordable housing. The neighborhood has welcomed people from around the country and world for the past century, but in recent years has drawn developers looking for the last low-cost patches of Manhattan.

The changes in East Harlem are only the latest in a spate of New York real estate deals pitting working-class tenants against corporate forces.

Late last year, the Stuyvesant Town and Peter Cooper Village complex of 11,000 apartments in Manhattan was sold for $5.4 billion, amid boisterous protests.

Earlier this year, a developer tried to buy the country's largest federally subsidized housing complex, Brooklyn's Starrett City. The $1.3 billion deal was blocked by the federal government, which said the prospective buyer had not demonstrated he could preserve the complex as affordable housing.

Many of the tenants in the affected buildings in Harlem are working-class immigrants from Mexico and Ecuador who are paying about $1,000 a month for one- and two-bedroom rent-stabilized apartments, Haro said.

Ana Laura Merino, from Puebla, Mexico, lives on 116th Street with her 7-year-old daughter and husband, who works in a bakery. "We won't go. The landlord is powerful, but we want to stay and fight for our rights," she said in Spanish.

On Tuesday in another part of East Harlem -- on Fifth Avenue at the edge of Central Park -- residents there were also up in arms over a development project.

A community garden they've tended for almost 20 years was bulldozed on Tuesday to make way for luxury condominiums adjoining the new Museum for African Art that is to open in 2009.