MOSCOW — Boxer Maxim Dadashev died Tuesday, four days after suffering a brain injury in a fight in Maryland. He was 28.

The Russian Boxing Federation said Dadashev suffered a brain swelling in Friday’s light-welterweight fight with Subriel Matias at the Theater at MGM National Harbor in Oxon Hill, Maryland. He underwent surgery but his heart stopped Tuesday, the federation said.

Dadashev was hospitalized at UM Prince George’s Hospital Center shortly after the fight, which was stopped by his corner following the 11th round after Dadashev took numerous shots to the head.

Footage from the fight shows Dadashev shaking his head in his corner as his trainer, Buddy McGirt, pleads with him to stop the fight, telling him: “You’re getting hit too much, Max. Please, Max, please let me do this.”

Shortly after, the referee stopped the bout at McGirt’s request.

The Russian Boxing Federation’s secretary general, Umar Kremlev, said the federation would investigate whether anyone was at fault for Dadashev’s death.

“We need to know the truth about what happened,” Kremlev wrote in an email to The Associated Press. “I believe that some human factors intervened, that there was some kind of violation.”

He added the federation would give Dadashev’s family financial support.

Both fighters were 13-0 before the bout, which offered the winner the right to challenge IBF titleholder Josh Taylor.