A Swiss football club is investigating claims that some of its fans urinated into the drinking bottle of an opposition goalkeeper.

The vile incident occurred during a lower league derby between FC Muri and FC Baden.

FC Muri keeper Reto Felder unwittingly drank from the water bottle which had been filled with Baden fans' urine. According to Swiss tabloid Blick, supporters persuaded a ballboy to pass them the bottle in which they then deposited bodily contents.

"I took one sip and realised that it was warm but thought that it was because of the sun, but by the second sip I realised that something was wrong," Felder is quoted as saying by Reuters.

According to Blick, fans chanted that the goalkeeper now "had AIDS" after he drank from the bottle.

The Swiss FA are investigating the incident and Felder has unsurprisingly threatened to take legal action.