"Sad news! Trifon Ivanov has passed away," the BFU said in a statement. "He will go down in Bulgarian football history as one of the greatest defenders."

Ivanov's rugged looks and dogged perseverance on the pitch earned him the nickname 'The Wolfman' during his years with national team from 1988 to 1998, during which he made 77 appearances and scored six goals.

Along with legendary striker Hristo Stoichkov and midfielder Yordan Lechkov, Ivanov was part of the Bulgaria team that reached the semi-finals in the 1994 World Cup in the United States.

He was voted Bulgaria's best football player in 1996 and was three times Bulgarian champion with CSKA Sofia.

In 1996, he also won the Austrian league title with Rapid Vienna.