Disney World moved ahead on Saturday with a contentious plan to allow guests back into parts of its sprawling resort, even as coronavirus cases in Florida continued to surge.

Visitors with advance reservations could gain access to the resort’s two most popular amusement parks, Magic Kingdom and Disney’s Animal Kingdom, beginning on Saturday. Disney World’s other major parks, Epcot and Hollywood Studios, are set to reopen on Wednesday.

Other amusement parks are also opening. Dorney Park in Pennsylvania and Cedar Point in Ohio also announced they would open to all guests on Saturday, after exclusively allowing season pass holders for several days. SeaWorld Orlando also resumed operating its rides and marine exhibits on Saturday.

All of the reopening parks have announced strict measures to limit crowds and regularly clean rides, in accordance with guidelines for amusement parks laid out by the Centers for Disease Control and Prevention. Temperature screenings at entrances are being enforced, and masks are generally required inside. Seats on some roller coasters are being left empty to promote social distancing, and some rides that cannot accommodate distancing requirements are closed.

Cedar Point announced that it would initially operate at about 20 percent capacity. Hershey Park in Pennsylvania, which reopened last week, said it would require guests to wear masks even in pools and water rides.

But even with amusement parks reopening at reduced capacity, fears remained that large resorts could spread the pandemic, especially in states where cases have spiked in recent days. Ohio on Friday set a single-day record with 1,525 new cases, and Florida hit daily records twice in the last 10 days, and has surpassed 10,000 daily cases five times in that period, announcing 10,360 new infections on Saturday.

In anticipation of the reopening, Disney employees anonymously created an online petition asking the company to keep its parks closed until new infection rates declined. As of Saturday morning, the petition had gathered over 20,000 signatures.

Amusement parks reopening abroad have been forced to grapple with similar concerns. A park in Japan implored visitors to “scream in their hearts,” rather than aloud, out of fear that shrieking patrons could spread aerosols containing the virus.

The park also shared a demonstration video of two mask-clad riders silently coursing over a steel roller coaster’s precipitous falls and sharp banks.