Local media footage showed rescuers in hard hats working from an elevated platform and a perch atop the ride’s support beams aiding the roller coaster’s occupants, one of whom could be seen gripping a safety harness.

LOS ANGELES  — Two dozen people, four of them slightly injured, were left stranded high off the ground after a roller coaster ride struck a tree branch at a Six Flags amusement park in southern California on Monday evening, fire officials said.

The Ninja roller coaster, which races at highway speeds suspended from an elevated track, stalled about 20 to 30 feet in the air, leaving some of its occupants trapped in the ride’s open cars for more than two hours before they were rescued.

The trouble at Six Flags Magic Mountain in Santa Clarita, California, about 30 miles (48 km) northwest of Los Angeles, started at about 6 p.m. local time when the ride struck a branch of an adjacent tree, Los Angeles County Fire Department spokesman Michael Pittman said.

Department spokesman Ed Pickett said the last of the 24 riders stranded by the mishap were extricated by about 8:30 p.m.

Local media footage showed rescuers in hard hats working from an elevated platform and a perch atop the ride’s support beams aiding the roller coaster’s occupants, one of whom could be seen gripping a safety harness.

The park said on its website that the Ninja was temporarily closed after the accident. Park officials did not immediately respond to requests for comment.

“Ninja pivots with precision as you narrowly miss tagging land and water, whipping around at 55 miles per hour,” according to the website, which describes the suspended, swinging roller coaster as one of only four such rides in the United States.

Four of the riders suffered minor injuries and two of them were sent to a hospital for treatment, Pickett said.