SINGAPORE - Four men are under investigation for allegedly using abusive language towards three public servants and a public service worker in four separate incidents, the police said on Wednesday (Sept 8).

On July 31, a 53-year-old man allegedly hurled vulgarities at a bus driver when he was advised to wear a mask properly while in the bus near Paya Lebar MRT station. The man's mask had dropped below his nose, prompting the driver to remind him to fit it tightly against his face.

But he followed the driver back to his seat and allegedly cursed him, the police said in a statement.

The second incident took place at Geylang Serai Market on Aug 5, when a safe distancing enforcement officer attached to the National Environment Agency was allegedly threatened and cursed by a man after telling him to wear his mask properly.

The man, 81, had his mask pulled below his mouth.

The men in both incidents are assisting with police investigations for using abusive language towards a public service worker or public servant and failing to comply with safe distancing measures.

In a third incident on Aug 7, a 51-year-old male passenger refused to wear a mask while inside a taxi despite being offered a mask by the taxi driver.

The driver observed that the man was visibly intoxicated and was not wearing a mask when he was picked up.

When the police arrived, the man still refused to wear a mask and allegedly hurled vulgarities at the police officers.

He was subsequently arrested for using abusive language towards a public servant and allegedly causing annoyance in a public place while drunk. He is also assisting with police investigations for failing to comply with safe distancing measures.

The fourth incident took place at a coffee shop in Whampoa Drive on Aug 12, when a safe distancing enforcement officer attached to the Singapore Food Agency was cursed by a 34-year-old man.

The officer was performing her duties and advising on safe distancing measures with another patron when the man allegedly hurled vulgarities at her.

He is assisting with police investigations for using abusive language towards a public servant.

The police reminded the public to take the prevailing safe distancing measures seriously.

Individuals who do not wear a mask properly outside of their place of residence can face a fine of up to $10,000 and/or jail time of up to six months.

Those who use threatening, abusive or insulting words or behaviour towards a public servant can be jailed for up to a year and/or fined up to $5,000.

The offence of causing annoyance while drunk is punishable with a fine of up to $1,000 and/or jail for up to six months.