At least four people have been killed and nine people injured after the Rajdhani Express, a high-speed luxury train, derailed in the northeastern state of Bihar, India, in the early hours of Wednesday.

The incident occurred just after 2 a.m. local time (4:30 p.m. EDT), when 12 cars of the train bound from New Delhi to Dibrugarh in the state of Assam in the far-east corner of India, went off the rails at the Golden Ganj train station. Authorities reportedly suspected “sabotage” by Maoists, a communist separatist group active in the country's east, as three bombs linked to a timer were recovered from Dariyapur, a village about 1.8 miles from the site of the derailment, until a local judge dismissed speculation linking the bombs to the derailment.

"We are ruling out sabotage prima facie in the Rajdhani derailment," Kundan Kumar, reportedly said, adding that the accident is being investigated. Kumar also said that the casualty number would be higher if it was an act of sabotage, The Economic Times reported, citing Press Trust of India, or PTI.

A senior police official in the area also reportedly ruled out sabotage as the cause behind the accident. "The driver said he heard no sound of explosion. The train stopped after some noise on the tracks," Vinod Kumar, said, according to DNA, a local news agency.

However, chairman of the Railway Board, Arunendra Kumar, told PTI: “Prima facie, it appears to be a case of sabotage. There was a blast on the track, which could have caused the derailment." He also reportedly said: "Another goods train, 60 kms (37 miles) away from the station, also got derailed due to a blast."

Home Minister Rajnath Singh said, according to Times Now, that Prime Minister Narendra Modi is being updated on details about the derailment, and added that it is too early to assign cause or blame any group until more details about the incident became available.

India's railway ministry reportedly announced a compensation of 200,000 rupees ($3,313) for the families of those killed in the accident, 100,000 rupees ($1,657) for those seriously injured and 20,000 rupees ($331) for those with minor injuries.

Rajdhani Express, which was introduced in 1969 and is positioned as a premium product, connects the nation's capital, New Delhi, to major cities across India through the country's vast but ageing and accident-prone rail network.