SHANGHAI, May 14 (Reuters) - Chinese robotaxi operator

Pony.ai said on Wednesday that one of its cars caught fire while

being handled by service staff after a system malfunction, but

that no passengers were onboard.

The vehicle was operating without a human driver on the road

on Tuesday morning when it showed an "abnormal status",

prompting the vehicle's safety protection mechanism to initiate

an emergency stop, Pony.ai said.

"No collision occurred and no one was injured. Service

personnel arrived at the scene within two minutes upon receiving

the alert. During the handling process, the vehicle caught

fire," it said in a statement.

"The specific cause is currently under investigation."

The incident could fuel further concerns over the safety of

autonomous driving in China. Chinese regulators have recently

moved to tighten the marketing and promotion of such features

following a fatal accident involving a Xiaomi ( XIACF ) car that

had been on autopilot mode.

One video posted on Chinese social media on Wednesday showed

plumes of black smoke billowing from a road in Beijing as cars

continued to drive in the reverse direction on a three lane

motor way.

Later, it showed emergency personnel putting out a fire of a

burnt out car that had mounted a road divider. The poster of the

video said it belonged to Pony.ai. Other photos and videos of

the car posted online showed that it bore the logo of a Lexus, a

luxury car brand of Japan's Toyota ( TM ) which is a backer of

Pony.ai.

Reuters was unable to independently verify the social media

posts and it was unclear from the videos and photos posted

online which Lexus model it was.

Qingdao city's radio and television station published an

interview on Wednesday with an unidentified Beijing traffic

police officer who said that the Pony.ai car caught fire when

the engine was ignited for a restart.

Pony.ai did not immediately respond to a request for further

comment. Toyota ( TM ) did not immediately respond to a request for

comment.

China has for years been encouraging progress in autonomous

driving technology and has granted robotaxi operators including

Pony.ai and Baidu ( BIDU ) permits to deploy robotaxis without

humans in the driving seat on some open Chinese roads.

Last year, an incident in San Francisco involving a crowd

setting on fire an autonomous Waymo robotaxi which had driven

into streets crowded with revellers sparked a debate about the

ability of robotic cars to make judgments.