Kolkata: Eighteen people were injured in a low intensity blast on board a local train on the outskirts of Kolkata on Tuesday morning.

The incident happened at around 4am local time when two rival groups travelling in the train clashed and hurled bombs at each other. The blast took place in the fifth compartment from the engine of the local train, under Eastern Railway’s Sealdah Main section.

The injured have been admitted to RG Kar Medical College and Hospital.

According to RN Mahapatra, Chief Public Relations Officer, Eastern Railway, the train left Sealdah station at 3.20am and reached Titagarh station at 3.55am. The blast took place just after a person boarded the train at Titagarh station.

“It looks like a crude bomb but what made the two group clash, that too in the wee hours of the morning, is still being investigated. Was it a predetermined or there are some other reason that needs to be known,” said a Railway Police Official. Security has been beefed up across all stations in and around the city to ensure passenger safety, he added.

“All those admitted due to the blast have critical injuries but are said to be stable,” a doctor treating the injured at a nearby government hospital said.

Meanwhile, opposition parties have claimed that the two groups belonged to the ruling Trinamool Congress (TMC) and the incident happened due to political rivalry.

“How can two rival groups sit in the train early morning and decide to throw bombs at each other.” BJP leader Siddharth Nath Singh asked, demanding a full probe into the incident.

Though there has been no reaction from the TMC citing that this does not fall under the jurisdiction of the state police, daily commuters have been alarmed by the incident.

“If group rivalries now take place inside train compartments, there is hardly any security for the average person. Had this incident taken place during peak hours, hundreds would have been injured,” said Prakash Miaty, a daily passenger.

“Who ever is responsible should be brought to justice or else our life is at stake. All these years we were in lookout for pickpockets and other thieves now we have to search co-passengers fearing that they may be carrying bombs,” said Arpita Kundu, who travel in that same local every day.