Nearly 1,300 revellers were treated for heat-related problems at Toby Keith's Oklahoma Twister Relief Concert on Saturday (06Jul13).

The singer organised the benefit gig at the Oklahoma Memorial Stadium in Norman, Oklahoma and took to the stage alongside fellow country greats Garth Brooks, Trisha Yearwood and Willie Nelson in front of a 60,000-strong crowd.

However, scores of concert-goers were forced to seek medical attention after falling ill in the extreme heat with 170 people requiring further treatment and 21 taken to local hospitals, according to Norman Regional Health System spokeswoman Kelly Wells.

Money raised from ticket sales will benefit the United Way of Central Oklahoma organisation which has established a fund to aid victims of the tornadoes and violent storms that ripped through the state in May (13), killing dozens of people.