One of the nation’s largest owners and operators of apartment homes is trying to halt Airbnb listings of its units. Apartment Investment & Management Company (Aimco), a property manager that oversees more than 50,000 properties, has filed a lawsuit in both California and Florida to prevent Airbnb from listing its units, saying that doing so violates its leases.

Read more: The Airbnb Factor

“It is not acceptable to us that Airbnb actively promotes and profits from deliberate breaches of our leases, and does so in utter disregard of the disrespectful and unsafe situations created for our full-time residents and their families,” Aimco CEO Terry Considine says.

Many landlords have been tentative about Airbnb from the onset. The home-sharing company allows individuals to rent out spaces in their homes to guests.

Aimco officials say this fall they have reached out to Airbnb three times to tell the company that listing its units on its platform violated its leases. Aimco says the company continued to maintain its listings.

Airbnb has not released a public comment yet about the pending lawsuit. However, Airbnb spokesperson Nick Papas did say: “This attack on the middle class by powerful interests is wholly without merit.”

Aimco officials argue that Airbnb’s “transient” guests may pose security risks to its residents. Aimco says that its residents must undergo background checks and credit history reviews prior to renting from its company.

“We are asking the courts to compensate Aimco for our losses and to enjoin Airbnb from participation in further illegal activity at our properties so that our law-abiding residents can enjoy a high-quality living experience,” Considine says.

Airbnb has been attempting to mend its relationships with landlords in recent months. In September 2016, Airbnb created a new program called Airbnb Friendly Building Program, which allows landlords to monitor how their tenants are listing and renting their apartments on Airbnb. Building owners can apply for the program and if accepted, they are able to set the terms for renting a unit in their building. But that also means the landlords likely will take a certain percentage of any money earned off the subleasing of the listing on Airbnb.

Source: “A Big Property Landlord Is Fighting Back and Suing Airbnb,” Business Insider/SFgate.com (Feb. 17, 2017) and “Denver Apartment Operators Sues Airbnb, Alleging ‘Illicit Subletting,’” Denver Business Journal (Feb. 17, 2017)