It's happening in Harlem and in the south Bronx.
And the practice is raising some eyebrows as some are asking whether select residents are being singled out.
Juan is a tenant in the south Bronx and he happens to be an un-documented immigrant.
But he's lived there for the past six years and like many others, he's now receiving letters from his new landlord, Liberty Place property management. The letters saying he owes thousands in back rent for the past 4 months, but Juan has proof that he's all paid up.
Another woman, also undocumented, who's lived here with her family says the same thing; The property manager also telling them that if they want to renew their leases and stay here, they have to be American citizens.
"If you're not legal in this country, we cannot give you a new lease (is what they said)," according to Juan.
Many of the tenants who got letters also live in Harlem, in several other buildings.
They were told they have to present their social security numbers.
Advocates for the tenant tell Eyewitness News, the only time a landlord is allowed to ask for a social security number, is if a tenant is filling out an application for a credit check, not when a tenant is already in an apartment.
So we figured we'd ask the management company at their office at Columbus Circle.
They didn't seem ready to explain much of anything.
Someone in the office said they hired a Public Relations company.