“The insults against Youssoufa Moukoko are unbearable and absolutely unacceptable,” North Germany football federation (NFV) president Guenter Distelrath said on Monday.

Distelrath is also DFB vice president responsible for anti-discrimination matters.

“I would appreciate if an independent sports jurisdiction also sends a clear message,” Distelrath said.

DFB integration representative Cacau also reacted with dismay.

“That can’t be. I strongly condemn it,” he told dpa. “It’s always sad when something like this happens. It feels like things like this have been happening more often in the past years.

“We shouldn’t capitulate in front of these people. If possible I think it’s always better to identify and ban them from the stadiums instead of stopping the game.”

During under-19 derby between Schalke and Dortmund on Sunday, Moukoko was repeatedly insulted by Schalke fans after scoring a hat-trick. The insults could be heard in the live stream of the game won by Dortmund 3-2.

After the match Schalke apologized for the fans’ behaviour including the ‘No To Racism’ hashtag in their Twitter post.

The club also said they hope to identify the fans and take necessary measures.

“I’m proud to have been born with this skin colour, and I will always be proud #BlackLivesMatter,” Moukoko posted on Instagram.