A train at Dhoby Ghaut MRT station was evacuated yesterday, after smoke was spotted coming out of a passenger's mobile phone.

The cause of the smoke was accidental and electrical in origin, said the Singapore Civil Defence (SCDF), which was called in to help investigate the phone after the incident.

No fire or injuries were reported in the incident, which happened on the North-East Line, said rail operator SBS Transit.

Passengers were evacuated as a precaution, said Ms Tammy Tan, senior vice-president of corporate communications at SBS Transit.

The SCDF and the Public Transport Security Command were also activated as a safety measure in response to the incident, said SBS.

The SCDF said its help was not required at the station.

The affected train was sent back to the depot.

A Straits Times reader, who declined to be named, said he was in the train and standing about 1m away from the owner of the phone, when smoke starting coming out of the device, which was in the man's back pocket.

The train was moving towards Dhoby Ghaut MRT station.

"The phone owner was just chatting with another two friends. But suddenly, he struggled to retrieve his phone, before throwing it down onto the floor," he said. "Thick smoke was coming out from the phone, but there was no fire."

He said the phone burned a slight hole in the owner's pocket, and the owner had soot on his hand after the incident.

At Dhoby Ghaut MRT station, passengers disembarked and two station staff helped move the crowd safely out of the train, he said.

It is believed that the phone model was an Honor, a smartphone brand under Huawei.

Mr Larry Yeung, 31, who was also on board the train, said: "Everything seemed normal, but after the train doors closed, they opened again.

"The train stopped for about a minute or so, and soon after, the announcement came to request that all passengers get off the train."

Mr Yeung, who works with design methodologies to solve problems, said the reason for the announcement was not stated and that commuters were calm throughout the entire incident.

The train then left the station.

While the disembarkation of the train meant that the platform was "very crowded", Mr Yeung said that there were no delays affecting the line and the subsequent train came in about 1½ minutes.

"I was lucky to get on the next train, but I saw that some didn't manage to get in," he added.

Correction note: This article has been edited for clarity.