Severe Turbulence Forces Plane's Emergency Landing in Ireland

Twelve people were taken to the hospital for treatment.

"A total of 12 people were transported to hospital, nine adults and three children. Two of the 12 were crew members," Limerick's University Hospital said in a statement, adding that the main injuries were "soft-tissue injuries, minor head injuries and lacerations."

One patient, a flight attendant, is still being assessed, United Airlines said in a statement, and 11 have been discharged. They are on their way back to Shannon Airport to continue their journey to London.

Nikki Hartin Boriack was one of the passengers. Speaking to ABC News, Boriack said there was a sudden drop, long enough for her to think about it. "There were a lot of little kids on the flight, so we are worried about them," Boriack wrote on Facebook, adding: "People literally we flying through the plane. ... We were trying to hold down the girl next to us to buckle her in."

The cause of the turbulence is unknown at this point.