A passenger train derailed during the morning rush hour in Hong Kong on Tuesday leaving eight people injured, authorities said.
Images from the scene showed three carriages off the tracks and zigzagged across the rails near Hung Hom station in Kowloon -- a busy interchange that provides services to mainland China.
Passengers had to leave the train through a broken door and cross tracks on the East Rail Line to make their way to safety.
Five hundred passengers had been evacuated from the train. Eight passengers reported injuries when they arrived at the concourse of the station, according to authorities.
The cause of the derailment was still under investigation but there was no immediate suggestion of foul play after previous attacks by pro-democracy protesters on the city's mass transit system.
"We would not rule out any possibility but at this stage we won't speculate on any particular suggestions," the city's transport chief Frank Chan told reporters.
Lau Tin-shing, operations director of the city's only rail company, the MTR Corporation, told media that short section of the track nearby had been replaced on Monday and the condition of the replacement is "not unusual", according to his visual assessment.
Subway services between two stations on the line were suspended and intercity services to mainland Chinese cities including Guangzhou, Dongguan and Beijing were cancelled for the day, according to MTR.
Hong Kong is in its fourth month of political unrest, which has seen millions of protesters hit the streets in the biggest challenge to Chinese rule since the city's handover from Britain in 1997.
Sparked by a now-withdrawn bill to allow extraditions to the mainland, the protests have turned increasingly violent with clashes between police and hardcore protesters becoming frequent.
MTR has been targeted by protesters since the company refused to hand over CCTV footage of police last month beating demonstrators and passengers on a subway train.
Protesters have vented their fury by vandalising entrance barriers and ticketing machines and smashing windows in several stations.
MTR chief executive Jacob Kam told the Financial Times in an interview published before the derailment that the protests were an "unprecedented" challenge and that the firm has been struggling to cope.
"It is getting more and more difficult because we are running out of spares," he told the FT. "In fact, what we've done is we have cannibalised parts from other stations and brought them to the damaged stations to try to keep things running."