A word of advice to young Thai lovers on Valentine's Day: No kissing in public.

Bangkok police say they plan to protect underage couples from the sting of Cupid's arrow, and will crack down on what is deemed to be "inappropriate" behavior.

Patrols will start after school hours in "high-risk areas" such as public parks, shopping malls and restaurants, said Police Lt. Vorawat Amornviwat of the Metropolitan Police Bureau.

The patrols will expand in the evening to include nightclubs, bars and so-called love motels, which rent small rooms for short periods of time.

"If we find teenagers below 18 engaged in inappropriate behavior like kissing, we will give them warnings and report to their parents so they can pick them up," he said. "Alcohol is definitely a catalyst for this kind of behavior, so we will keep an eye on underage drinking."

The Metropolitan Police force also has asked nightclub and bar owners to help by turning away underage customers.

"These places are not meant for kids," he said, adding that Valentine's Day required extra vigilance "because they seem to be more vulnerable to sexual temptations on this particular night."

The crackdown on public displays of affection is the latest effort to balance the country's look-the-other-way tolerance with Buddhist values of modesty and manners.

Over the weekend, the Culture Ministry issued what it called the "10 Commandments of Love" to encourage teens not to engage in sexual activities while celebrating Valentine's Day.