Firefighters conducted rescue operations in parts of the New Territories on Monday afternoon after a voltage dip left people trapped in lifts.

The authorities said the dip occurred at 3.17pm, with the police receiving multiple reports of the sound of an explosion at a CLP substation in Tsing Yi.

Online images showed a plume of smoke which appeared to be coming from a substation on Nga Ying Chau Street.

A spokesperson for CLP said the smoke was caused by an equipment malfunction at the substation, which also led voltage to dip, but it did not interrupt the power supply.

The firm apologised for the inconvenience and said staff members were investigating.

Roads in the surrounding area were cordoned off, but police said they found no fire at the scene and nobody was injured.

Firefighters said they received 20 reports of people trapped in lifts and several regarding automatic fire alarms sounding in Kwai Tsing, Ma On Shan and Sha Tin.