Police in the German city of Cologne are facing controversy over the use of an alleged racial slur to describe hundreds of North African men who were detained on New Year’s Eve.

There was initial relief when New Year celebrations passed peacefully in the city without any repeat of the sex attacks of a year ago.

But police were accused of racial profiling after it emerged that some 650 North African men were held on their way to the city centre.

Now fresh controversy has broken out over a tweet sent out on New Year’s Ever in which police described the detained men as “Nafris”.

“At the main station several hundred Nafris are currently being checked,” the tweet read.

Police have defended the tweet, claiming that Nafri is an internal police shorthand for North Africans and carries no derogatory connotations.

But others across the political spectrum claim the word is a racial slur.

“What’s the difference between Nafri and n****r?” Jan Böhmermann, one of Germany’s best known comedians, who was himself embroiled in controversy last year over his alleged insult of Turkey’s President Recep Tayyip Erdogan, asked on Twitter.