Hong Kongers are planning to hold a candlelight vigil night to mark the 1989 student-led Tiananmen Square protests.

The annual event on Thursday night takes on greater meaning for the city's young after last autumn's pro-democracy demonstrations sharpened their sense of unease with Beijing.

For the first time in the event's quarter-century history, some student groups won't be taking part and will instead hold their own memorials.

It's a sign of the emerging rift between young and old over Hong Kong identity that took root during the Occupy Central protests.

The vigil is the only large-scale public commemoration of the victims on Chinese soil.

Hundreds and possibly thousands of unarmed protesters and onlookers were killed when tanks and soldiers entered central Beijing on June 3-4, 1989.