Assou-Ekotto head-butt stuns Finke

Cameroon coach Volker Finke has vowed to get to the bottom of why Benoit Assou-Ekotto head-butted teammate Benjamin Moukandjo during the nation's 4-0 defeat by Croatia.

- Three Points: Croatia crush Cameroon

Cameroon's heavy loss versus Croatia, their second of the 2014 World Cup, confirmed they cannot progress beyond the group stage of the tournament.

The match in Manaus was an enduring 90 minutes for Finke's side, who had Alex Song sent off before half-time for an elbow in the back of Mario Mandzukic and then in the second half they saw Assou-Ekotto and Moukandjo clash.

"It's unimaginable. I saw this happen and I need to find out exactly what happened, why exactly these two players exploded," Finke said, according to the BBC.

"I hate to see that. It's not the image of Cameroon I want to project."

Song, meanwhile, later apologised for his part in the off-the-ball scuffle with Mandzukic which resulted in the Barcelona player heading back to the changing rooms ahead of schedule.

In a statement the 26-year-old said: "I'm very sad at the moment as I feel I have let my country and myself down.

"It was a stupid moment and I'm truly sorry. If I could do anything to take it back I would. Please forgive me.''

Information from the Press Association was used in this report.