Two men who took part in sexual hook-ups on a gay dating app found themselves being held to ransom - by a man called Ransom.

Okereke Ransom Okechukwu met the men separately on Grindr and threatened to circulate a video of one of them performing a sexual act unless he gave him money.

The Nigerian even threatened to kill the other man, an Australian who was in Singapore on a work trip.

Okechukwu, 34, was jailed for a year on Monday after pleading guilty to two counts of criminal intimidation. His victims cannot be named because of a gag order to protect their identities.

Court documents did not state why Okechukwu was in Singapore.

He met his first victim, a 36-year-old Singapore permanent resident, via Grindr on May 19 last year.

Okechukwu was invited to the man's home, where he used his cellphone to record a video of his victim performing a sexual act on him.

Deputy Public Prosecutor Lim Shin Hui said Okechukwu later demanded $500 from the man and showed him the video .

When asked to delete the video, Okechukwu refused and instead threatened to circulate it to "ruin" the man's reputation. The man later gave him $500 but Okechukwu, instead of deleting the video, asked him for another $500.

Okechukwu left the premises only when the man alerted the police.

Okechukwu communicated with his second victim, the 32-year-old Australian, via Grindr the next day and on May 22 last year they met at the victim's hotel room.

The man was performing a sexual act on Okechukwu when he heard a sound from the Nigerian's cellphone, indicating that a video was being recorded.

The Australian stopped what he was doing and the pair quarrelled, with Okechukwu demanding $1,500 from him. When the Australian refused to pay up, Okechukwu told him that he had a gun and threatened to kill him.

The man said he would try to get the cash from the hotel's reception. But when Okechukwu later stepped out of the room, the Australian locked him out and alerted security.

Furious, Okechukwu banged on the door but fled before security staff arrived.

Police managed to identify him through follow-up investigations and he was arrested at a hotel in Lorong 8 Geylang the following day.

Offenders convicted of criminal intimidation can be jailed for up to two years and fined.