SINGAPORE - A teenager who had sex with a minor - just one month into a probation term for a similar offence committed with a different girl - was on Monday placed on 21 months' supervised probation.

Lee Sze Kiat ran into his second victim, an acquaintance he had previously met through mutual friends, some time in September while performing community service for the earlier conviction.

He invited the 13-year-old home the next day and pressured her into having sex with him.

The court heard that Lee and his victim, both secondary school students, had met by chance at a community club near her home when she came to attend a mid-autumn festival celebration.

They chatted after he had completed his community service obligations for the day, and continued to communicate after parting ways. This led to Lee committing two offences the next day at his HDB flat in Boon Lay, when no one else was home.

Lee's first probation term, for having sex with a 15-year-old, is for a 15-month period. It includes conditions such as 80 hours of mandatory community service.

Under the terms of probation imposed on Monday, Lee, 16, has to perform 120 hours and remain indoors from 10pm to 6am.

His parents signed a $10,000 bond to ensure his good behaviour - twice the original sum bonded.

In the current case, Lee pleaded guilty to one count of sexual penetration and had another taken into consideration.

He could have been jailed for up to 10 years and fined for each count of having sex with a person under 16 years.