A man who was dressed as Batman villain the Joker has been arrested after allegedly stabbing 10 people onboard a Tokyo commuter train on Sunday, October 31.

The attacker also poured what is believed to have been oil around the carriage before lighting it on fire, causing panic among several passengers.

It was also reported that hydrochloric acid was thrown during the attack, which occurred on the Keio express line bound for Shinjuku, the world's busiest rail station in Japan.

One female student is believed to be seriously injured while at least nine others suffered injuries not believed to be life-threatening. 

According to local media reports, the 26-year-old suspect allegedly told police he became angry when he saw women who 'looked happy' and wanted to kill them. 

One video uploaded on Twitter showed a steady stream of people running away from a train car where, seconds later, a blaze lit up.

Another video showed passengers rushing to squeeze out of the train's windows and onto the platform where the train had made an emergency stop.

'I thought it was a Halloween stunt,' one witness told the Yomiuri newspaper, recalling the moment he saw other passengers running in a panic towards his train car.

'Then, I saw a man walking this way, slowly waving a long knife.'

The witness described how there was blood on the knife, he said.

One passenger, believed to be in his 60s or 70s lost consciousness after being stabbed, according to Kyodo News. 

It has not been confirmed by police if hydrochloric acid was sprayed on the train. 

A male passenger said: 'I heard a loud bang and saw flames and smoke in the back. Everyone was panicking,'

The attacker, a 24-year-old man, was arrested on the spot and is being investigated, NHK said. 

The incident was posted on social media by witnesses and footage on the television showed firefighters, police officials, and paramedics rescuing passengers.

Many passengers escaped through train windows after the doors failed to open immediately when it stopped.

Officers were seen entering the train where the suspect sat and did not resist arrest.

According to investigative sources the man wore a character outfit.  The motive for the attack was not immediately known but it happened on a train bound for Shinjuku in central Tokyo, made up of 10 carriages. 

It is the second attack involving a knife on a Tokyo train in two months, as a 36-year-old man stabbed 10 passengers on a commuter train in Tokyo in a random burst of violence the day before the closing ceremony of the Tokyo Olympics in August.