SINGAPORE - A man who was caught on video viciously assaulting another on the train on the Downtown MRT Line on Sunday morning (May 23) has been arrested.

The police said the 40-year-old man has been arrested for public nuisance, and will be investigated for voluntarily causing hurt.

In a release, the police said the assailant had been in an escalated dispute with the 24-year-old victim.

The police were alerted to a case of assault in the vicinity of Little India MRT station at about 10.15am.

But when officers arrived, the people involved were no longer at the scene.

A video of the incident shows the assailant raining blows on the victim on the ground, as the train rolls into Rochor MRT station.

The victim is heard making groaning sounds, as members of the public move away.

The suspect was subsequently identified and arrested.

Investigations are ongoing.

Ms Tammy Tan, senior vice-president of corporate communications at SBS Transit, which operates the Downtown Line, said the incident happened on the train that was heading towards Bukit Panjang.

She said an SBS Transit staff member was alerted to the commotion and immediately proceeded to the train car.

"He saw the victim alone and asked if he needed medical assistance," she said. "The latter, however, declined any assistance and said that the aggressor had already alighted. He insisted he was fine and proceeded on with his journey."

Ms Tan said SBS Transit will share its security camera footage with the police for their investigations.

The police said acts of violence will not be tolerated, and urged members of the public to call them if they see an assault taking place.

Videos of the incident should also be shared with the police, instead of being circulated on social media, the police added.