Posted April 14, 2017 12:35:04

Firefighters have rescued 20 people who were stranded 30 metres up in the air for at least four hours, after a roller coaster became stuck at a Six Flags America theme park in Maryland.

The Joker's Jinx roller coaster, which according to the park's website features a "cobra roll", "sidewinder loop", and "countless swift reversals", stalled on Thursday evening (local time).

Prince George's County Fire/EMS spokesman Mark Brady said on his Twitter account that the riders came to a standstill about 5:30pm.

Fire department officials said the riders were upright and no-one appeared to be in distress.

By 9:30pm local time, Mr Brady confirmed all riders were safely on the ground.

The looping roller coaster reaches speeds of 96 kilometres per hour and was introduced in 1999, according to the park's website.

Six Flags America said in a statement: "Joker's Jinx did not complete its regular ride cycle, causing it to stop at a safe location on the track".

"The safety of our guests is our highest priority and the ride will be closed for a thorough inspection before reopening."

Two dozen passengers became stuck, some for as long as five hours, on the same ride in August 2014.

AP

Topics: arts-and-entertainment, community-and-society, disasters-and-accidents, united-states