(REUTERS) - More than 650 modern pentathlon athletes have called for the executive board of the sport's governing body to step down after it decided to remove horse riding from the Olympic programme, a sports publication said.

The pentathlon body UIPM decided on Thursday (Nov 4) to remove horse riding from the 2028 Los Angeles Games after a broad outcry when a German coach punched a horse that refused to jump a fence at this year's Tokyo Games.

The athletes who signed the letter, including current and former Olympic medallists, said the executive board had"undermined 109 years of modern pentathlon" by taking a decision without consulting athletes and member federations, the site Inside the Games reported on Friday.

The UIPM did not immediately respond to a request for comment on Saturday.

"As modern pentathletes, past and present, we are shocked at the UIPM executive board's decision to remove the equestrian discipline," the athletes said in the letter.

"We unanimously declare a vote of no confidence in the president and complete executive board. Baron Pierre de Coubertin created modern pentathlon specifically for the Olympic Games to showcase the ultimate athlete.

"The board say they are responding to pressure from the International Olympic Committee. We are all aware of the challenges modern pentathlon faces. We must always look to the future and keep our sport moving forward."

The athletes said the UIPM needed a new board that would plan for the sport's "long-term interests" while also standing up for athletes and protecting the sport's place at the Olympics.

Modern pentathlon, an Olympic sport since 1912, has featured five events - fencing, swimming, equestrian showjumping, pistol shooting and cross-country running.

UIPM president Klaus Schormann had said although the decision to drop horse riding was "painful", the sport must change with the times.

The organisation is to hold elections during an online meeting on Nov 27 and 28.