The second of two Chinese national workers is escorted by Singapore Civil Defense Force officers after a protest in December last year. Pic: AP.

SINGAPORE (AP) — Police are investigating two Chinese men’s allegations that officers assaulted them while they were in custody over participating in Singapore’s first strike in three decades, the city-state said Tuesday.

The men said in separate interviews with a local documentary filmmaker in January that they were threatened and beaten by police during questioning. Both were among five bus drivers charged for involvement in the Nov. 26-27 strike which saw 171 Chinese immigrant bus drivers of a public transport company protesting over being paid nearly a quarter less than their Malaysian colleagues. The labor action disrupted about 5 percent of bus services in the city-state where such labor actions are almost unheard of.

(READ MORE: Response to bus strike a loss for all workers in Singapore)

The Ministry of Home Affairs said in a statement on Tuesday evening that it takes a serious view of the public allegations and that an independent office within the police force was investigating the men’s claims.

“Such allegations must be taken seriously as it has a detrimental impact on public confidence and trust in the integrity” of the police, it said. The investigators would seek assistance from bus drivers, the producers of the video and other related parties during the investigation, it added.

In one of the videos, Liu Xiangying said, “He (police officer) said, ‘Do you know I can dig a hole and bury you? No one will be able to find you.’ Those were the police’s actual words.”

Liu added that during the interrogation, he was beaten at the back of the neck and shoulder blades after denying that he ever knew another co-defendant, He Jun Ling. “He (police officer) showed me a photo of He Jun Ling. I said, ‘I don’t know him.’ Because I didn’t know He Jun Ling, he beat me,” said Liu.

He, who faces an additional charge of posting material online that instigated other bus drivers to strike, recounted in his separate video interview that he was questioned for eight hours and punched in the stomach.

“I was interrogated from 5 a.m. to 1 p.m. In between they punched me once. They locked me in a small room. At the time, a police officer handcuffed me and after that, he punched me in the stomach,” he said.

One of the drivers was jailed for six weeks and deported. Liu, He and two other drivers are out on bail and represented by lawyers while deciding whether they want to go on trial. If found guilty, they face up to one year in prison and a fine of up to $2,000.

Of the other drivers who went on strike, 29 lost their work permits and were deported them to China. The rest were issued warnings but were allowed to remain and work in Singapore.