At least 36 people were killed and 50 injured when the Jagdalpur-Bhubaneswar Hirakhand Express derailed in Andhra Pradesh's Vizianagaram district, police said on Sunday.

The incident occurred on Saturday at 11.30 p.m. near Kuneru station, 24 km from Rayagada in Odisha. The train was enroute to Odisha's capital Bhubaneswar from Jagdalpur in Chhattisgarh.

According to East Coast Railway spokesperson J.P. Mishra, nine coaches -- a luggage van, two general and four sleeper coaches, a second-cum-third AC coach, a third AC coach -- and the engine derailed.

"Four accident relief vans have been sent to the accident site. The reason behind the incident is yet to be ascertained," Mishra said.

Army personnel were also deployed for the rescue work.

According to the railways, 13 unaffected coaches left the accident site carrying passengers via Sambalpur and Angul. Thirteen buses were also arranged to carry the passengers to different destinations.

Officials said 22 injured people were shifted to the Parvathipuram government hospital. Seven patients were referred to Kin George Hospital in Visakhapatnam while seven were discharged after first aid.

A total of 32 injured were brought to the Rayagada district hospital.

As the accident site was enveloped in darkness, it took time for authorities to launch rescue and relief operations.

Rescue workers worked through the night to locate the trapped passengers and pulled them out from the wreckage.

Railway Minister Suresh Prabhu was on way to the accident site.

"Deeply pained and anguished at the loss of innocent lives," he tweeted.

Prime Minister Narendra Modi expressed shock over the accident. "My thoughts are with those who lost their loved ones," he said and prayed for their speedy recovery.

An inquiry by the Commissioner of Railway Safety has been ordered.

A railway official in New Delhi said sabotage cannot be ruled out.

"Sabotage is not ruled out as the area where the derailment happened was a Maoist area," the official told IANS.

The railways have announced Rs 2 lakh ex-gratia each for the next of the kin of the deceased and Rs 50,000 each for the injured.

The train had departed from Jagdalpur at 3 p.m. on Saturday and was scheduled to reach Bhubaneswar at 8.25 a.m. on Sunday.

It ran off the track minutes after it left Odisha and entered Andhra Pradesh, from where it would have re-entered Odisha.

Following the accident, train services have been suspended on the route. Some trains were cancelled or diverted.

The railways have set up helplines in Andhra Pradesh and Odisha.

The numbers for Vizianagaram are: 83331, 83332, 83333, 83334, 08922-221202, 08922-221206

Visakhapatnam: 83003, 83005, 83006, 0891-2746344, 0891-2746330, 08500358610, 08500358712

Rayagada: 06856-223400, 06856-223500, 09439741181, 09439741071, 07681878777

Khurda: 0674-2490670. Bhubaneswar station: 06742543360. Behrampur station: 06802229632.