On Tuesday, San Francisco’s Board of Supervisors voted 10-0 to approve a new rules that requires short-term rental websites like Airbnb to display each host’s registration number next to their listings or email the information to the city’s short-term rentals office, according to the SF Examiner. Any site that refuses to do so face fines of up to $1,000 per day.

The new rules would supplement San Francisco’s existing short-term rental regulations that passed in late 2014 and then went into effect in February 2015. Since then, 1,324 hosts have registered with the office, according to the SF Examiner, just a small fraction of the thousands of hosts who are required to under the current laws.

For city officials, forcing websites like Airbnb to display host registration numbers would be an effective way to make sure San Francisco hosts register their homes for short-term rental purposes. In turn, this can help officials better monitor rental activity in San Francisco and help ensure that no illegal hotels are created by landlords who turn would-be long-term housing into short-term units.

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Airbnb and other home-sharing services have been widely accused of exacerbating San Francisco’s housing crisis, though the company has vehemently argued that its service helps hosts pay their high mortgages and increasing rent.

However, the home-sharing company says that the current registration process for San Francisco hosts is too complicated and makes it too difficult for hosts to sign up. Instead, it says, the city should focus on improving that process.

Airbnb and other opponents of the new enforcement rules also argue that they go against a federal law that prevents San Francisco’s government from sanctioning the website for information posted by its users. City officials, however, argue that the new regulations are directed at Airbnb’s business activities, not its online content.

This latest move is part of an ongoing battle between Airbnb and San Francisco’s government. In November, the home-sharing company defeated a ballot measure that would have imposed stricter regulations on short-term rentals and therefore its business. Airbnb spent more than $8 million to defeat the measure.

“An estimated 1,200 San Franciscans avoided foreclosure or eviction by hosting on Airbnb, and this legally-questionable proposal puts their housing at risk without offering any real solutions to fix the complex process,” the Airbnb said in a statement.

It added: “The Board acknowledged that the registration system is broken and, in order to help people to be able to stay in their homes, The City needs to fix it. We hope the Board will act to fix this broken registration system, and we are considering all options to stand up for our community and keep fighting for real reform.”

The new rules could open the door for other cities that also require that hosts register to impose similar rules on websites like Airbnb.

It’s unclear whether Airbnb will begin to force hosts to submit their registrations numbers in order to post listings, though its statement suggests it won’t. Fortune has contacted Airbnb for a clarification and will update this story if we hear more.