Britain's Carl Froch has apologised for threatening to kill Mikkel Kessler in their IBF super-middleweight fight on Saturday but will still face a British Boxing Board of Control investigation.

Froch, from Nottingham, tweeted: external-link "I'm sorry if my comments offended anyone. This fight means so much to me and emotions are running high."

BBBC general secretary Robert Smith said the body would look into it.

"Carl's comments are inappropriate and we are disappointed," said Smith.

The rivals, who will meet at the O2 Arena in London, have been friends since their first bout three years ago, which 34-year-old Kessler won on points in his native Denmark.

But a desire for revenge led Froch, 35, to change his tune on Wednesday.

He told reporters: "On Saturday night, if I have to, I will kill [him]. It sounds brutal, it sounds horrible, but this is what it means to me.

Froch confident ahead of Kessler rematch

"I'm going to leave it in the ring. And when I'm smashing his face in, I am going to go for the kill. I am going to go for the finish."

Boxing history is littered with similar threats, but Smith said he was particularly disappointed to see them come from a fighter like Froch.

But he also said that the comments would not jeopardise the fight.

Smith said: "They are very uncharacteristic from Carl, who is usually a very well-behaved and measured young man.

"We are surprised and disappointed in his comments. I have spoken to his management team of Rob McCracken and Eddie Hearn and we are looking into it and will deal with it accordingly.

"Carl is licensed by the Midlands Area Council and they will deal with it as quickly as they possibly can. Obviously we are not in a position to do anything about it before the fight."

While acknowledging the pressure Froch is under before the fight, Smith stressed that it was no excuse.

Smith added: "This is Carl's biggest fight of his career - if he wins this he carries on and if he loses what does he do? It is a difficult time two or three days before the fight and he is right on edge.

"But being highly strung at the moment is no excuse. Carl is a decent young man and he is well aware that he shouldn't have said it.

"Up until now all the publicity surrounding the fight has been superb and this has dampened it somewhat."