SINGAPORE - Unhappy at being told to stop smoking at a bus interchange, a man pushed an elderly part-time security officer, punched and kicked him when he fell to the ground, while his colleague lay on top of the victim.

Two teachers, who happened to be at the Pasir Ris bus interchange, intervened and were assaulted as well.

On Thursday (Oct 5), Kuhaannath Pillai, 25, then a supervisor, was jailed for two weeks for causing hurt to Mr Abdul Hamid Abu Bakar, 73, and hitting the back of teacher See Wan Ting's head on Jan 23.

The assault on Mr Abdul Hamid was committed with Dinesh Gopi Nathan, 28, then an operations executive at Sun City Maintenance. He will appear in court again on Oct 16.

Kuhaannath was also fined $1,000 for disorderly behaviour by shouting and pushing a computer monitor belonging to Bedok North Neighbourhood Police Centre (NPC) on Dec 4, 2016.

Deputy Public Prosecutor Lu Yiwei said that at about 12.30am on Jan 23, Mr Abdul Hamid saw Kuhaannath, Dinesh and Mr Melvin Raj George Francis smoking at the bus interchange. He identified himself and told them to stop.

Kuhaannath and the victim soon began shouting and cursing at each other.

Subsequently, Kuhaannath pushed the victim in the shoulder, causing him to fall.

Dinesh rushed over and lay on top of the victim, who was then kicked and punched by Kuhaannath.

Teacher Lim Chih Chang, 42, and Ms See, 23, saw this and shouted at them to stop. Kuhaannath did so. Dinesh and Mr Melvin Raj helped the victim to a nearby bench.

Dinesh then allegedly punched Mr Lim once in his stomach area. Upon seeing this, Ms See struck him with a 1.5-litre bottle. Kuhaannath hit her in the back of her head, causing her to fall to the ground.

He also pushed Mr Lim, causing him to fall, and punched him.

When Dinesh asked Mr Lim why the two teachers were interfering in others' business, Mr Lim replied that the men were fighting and causing fear in public.

Mr Abdul Hamid did not seek medical attention. Both Mr Lim and Ms See sought treatment at a polyclinic for their minor injuries.

DPP Lu said the two accused had been drinking before the incident, and were on their way home.

In the other case, the court heard that Kuhaannath went to the NPC to ask about his girlfriend's case of alleged cheating. He claimed to be responsible and demanded to be arrested.

When he was told to return the next day for an interview, Kuhaannath became hostile and shouted, insisting that he be arrested. He stood up and pushed the computer monitor, which toppled and fell onto the table top.

He had drunk two cans of beer earlier.

In mitigation, his lawyer Timothy Ng said that his client, who is in the midst of a divorce, was concerned about his pregnant girlfriend and tried to take the blame for her alleged offence of misappropriating money from her workplace.

The lawyer added that Kuhaannath was remorseful for causing hurt to the security guard. He urged the court to impose a fine on his client for the offences of causing hurt.

Kuhaannath could have been jailed for up to two years and/or fined up to $5,000 on each charge of causing hurt; and fined up to $2,000 and/or jailed for up to six months for disorderly behaviour.