New Delhi, Nov. 26 -- Four people were killed after a massive fire engulfed several high-rise towers of a residential complex in Hong Kong's northern Tai Po district, with thick grey smoke billowing out as emergency services tackled the blaze.

The government says three people remain in critical condition and another is seriously injured. The fire has been designated a level-five incident - Hong Kong's most severe classification - and some residents are reportedly still trapped inside the buildings, although this has not been confirmed. Images, videos on social media show flames racing up bamboo scaffolding surrounding the high-rise blocks as firefighters continue their efforts to contain the blaze.

Meanwhile, Hong Kong's Transport Depar...