Two men were arrested after they allegedly fought over a toilet urinal in Aljunied MRT station on Sunday.
The police said they were alerted to a call for assistance at 8.20pm at 81 Lorong 25, Geylang.
Two men, aged 32 and 29, were arrested for affray, the police added.
In photos sent to citizen journalism site Stomp, at least three police officers were seen confronting a group of men.
The two men were arguing over whose turn it was to use the last available urinal in the toilet, said the netizen who sent the photo to Stomp and was identified only as Leonard.
"It escalated into a big fight, from inside the toilet to outside, that also involved the men's respective companions," he told Stomp.
"Everyone else got out of the toilet."
Leonard subsequently alerted officers from the Public Transport Security Command, who were patrolling the area, to the dispute.
The officers then approached the men to break up the fight.
Police investigations are ongoing.