Logos of Airbnb are displayed outside a media event in Johannesburg in July. (Waldo Swiegers/Bloomberg)

Airbnb has hired a trio of Democratic lobbyists at the high-powered lobby firm Podesta Group, marking an increase in the company’s Washington lobbying presence at a time when “sharing economy” companies like Airbnb and Uber are drawing scrutiny from federal and local lawmakers.

The San Francisco-based online home rental site hired Podesta in September, according to a lobbying disclosure filing. The filing does not specify what the lobbyists are working on, beyond “issues related to the sharing economy.”

The lobbyists are Oscar Ramirez, a former top aide to Labor Secretary Hilda Solis; Paul Brathwaite, the former executive director for the Congressional Black Caucus who also served as a Labor Department senior staffer under President Bill Clinton, and Claudia James, a former policy adviser for Rep. James E. Clyburn (D-S.C.).

“We’re always working to educate policymakers about Airbnb and how our platform expands the economic pie for ordinary people by helping them earn extra income that they use to pay the bills,” Airbnb spokesman Nick Papas said.

The ramp-up in Airbnb’s lobbying comes at a time the company is facing growing criticism from the U.S. hotel industry, which has long argued Airbnb should be subject to the same regulations as hotels. The American Hotel and Lodging Association, a trade group, recently launched a campaign to urge federal lawmakers to increase their scrutiny of Airbnb’s practices — arguing that Airbnb rentals drive up housing prices and restrict housing stock.

In July, Democratic Sens. Elizabeth Warren (Mass.), Dianne Feinstein (Calif.) and Brian Schatz (Hawaii) sent a letter to Federal Trade Commission Chairwoman Edith Ramirez asking the agency to investigate to what degree people are using Airbnb and similar sites to run full-time rental businesses and how that is affecting local communities.

“We are concerned that short-term rentals may be exacerbating housing shortages and driving up the cost of housing in our communities,” the lawmakers wrote. “We have also read troubling reports of racial discrimination on some short-term rental platforms. Furthermore, we are concerned that communities and consumers may be put at risk through violations of sensible health, safety and zoning regulations under state and local law.”

Airbnb hit back earlier this month, sending a memo to lawmakers framing the hotel trade group as anti-union, the Hill reported last week.

Podesta is the second lobby firm Airbnb has brought on this year. In January, the company hired former Minnesota congressman Vin Weber, a partner at the lobby and public affairs firm Mercury, to lobby on antitrust, e-commerce and economic development issues. Airbnb has paid Mercury $100,000 in lobbying fees since then.