By Lisa Maria Garza

DALLAS (Reuters) - A woman died on Friday following an accident on a roller coaster at the Six Flags Over Texas amusement park in Arlington, the park operator said.

The unidentified woman was riding the Texas Giant roller coaster ride at the park in Arlington, about 20 miles west of Dallas, when the accident occurred, Six Flags said in a statement.

"Since the safety of our guests and employees is our number one priority, the ride has been closed pending further investigation," Six Flags spokeswoman Sharon Parker said.

"Our thoughts and prayers are with the family and friends during this difficult time," she added.

Parker gave no further details of the accident.

At the time that it opened in 1990, the Texas Giant ride was promoted as the tallest wooden roller coaster in the world.

The wooden tracks were replaced in 2010 with steel but the original wooden support structure was kept and the lift hill was elevated 10 feet, according to the Six Flags website.

In a separate incident at an amusement park in Sandusky, Ohio, seven people were injured on Friday evening when a boat ride they were on slipped backwards on a lift.

The Cedar Point amusement park said in a statement the ride attendants stopped the Shoot the Rapids water ride when the accident occurred on the ride's first hill.

Six of the seven riders were treated at the park by emergency responders and released. One passenger was taken to a hospital with unknown injuries and later released, the park said. Cedar Point is located about 60 miles west of Cleveland.

The ride will remain closed until the Ohio Department of Agriculture, which regulates amusement rides, completes its investigation.

[Wooden rollercoaster in Kemah near Houston, Texas, USA via]

(Reporting by Lisa Maria Garza; Editing by Tim Gaynor and Eric Beech)