Germany coach Joachim Loew has branded the bullying of Cologne’s Kevin Pezzoni by fans as “unacceptable” after the defender was forced to quit the second division club after being threatened.

“It is unacceptable that this could happen,” Loew said ahead of Germany’s opening World Cup qualifier against the Faroe Islands on Friday in Hanover.

“We have to seriously consider how to avoid such things happening in the future.”

Nearly three years after Germany international goalkeeper Robert Enke committed suicide after suffering from depression, there was deep concern after Pezzoni, 23, quit Cologne having been confronted by menacing fans at his home last week.

A group of supporters targeted him by leaving a note on his car, threatening him with violence, then aggressively confronted him at home after organising themselves using the Internet.

Having joined Cologne in 2008 from Blackburn Rovers, Pezzoni, who had his nose broken by a fan in February while celebrating in the city, told club coach Holger Stanislawski he no longer felt safe playing for the team.

Cologne have agreed to Pezzoni’s request to have his contract terminated.

Germany’s team manager Oliver Bierhoff, who spent a decade playing in the Italian league between 1991 and 2001, said he had witnessed similar things and called for them to be stamped out of football.

“I personally know of situations like this from my time in Italy,” said the 44-year-old.

“These aren’t fans, they are criminals who have to be watched and pushed out of the sport.

“It is not an easy thing to do, but we should not trivialise the issue and we have to work together to address it.

“Such a thing we don’t want to see in the sport, it has nothing to do with football.”