Hong Kong -- Lighting injured three airplane maintenance workers at Hong Kong International Airport and they have been sent to a nearby hospital for treatment, local media reported on Sunday.

All of the three people were clear-headed on their way to the hospital.

The Hong Kong Airport Authority has already introduced an Airport Lighting Warning System in 2003 and two Red Light Warnings were issued earlier in the day.

A Red Lighting Warning is issued when a lighting strike is detected at the airport or the threat of a lighting strike is very high. When the Red Light Warning is activated, all ramp activities will stop immediately while airport staff and passengers are advised to stay inside sheltered areas.