(CNN) Two dozen riders were stuck on a stalled roller coaster for more than three hours Thursday night at Six Flags America in Largo, Maryland, authorities said.

Firefighters arrived at the amusement park about 6 p.m. ET and began working to safely bring down 24 riders stranded on the Joker's Jinx, said Mark E. Brady, spokesman for the Prince George's County Fire Department.

The final riders were not helped down until after 9 p.m. ET, Brady tweeted.

No injuries were reported.

On its website, Six Flags America says the ride normally lasts for just over a minute and reaches a speed of 60 mph.

Read More