NDRF, RPF and CRPF teams carried out the relief and rescue operations. The train was travelling from Jagdalpur in the state of Chhattisgarh to Bhubaneswar, the capital city of the eastern state of Odisha.
A railway official in New Delhi said sabotage can not be ruled out.
The accident came only two months after almost 150 people were killed in a similar disaster, highlighting the poor state of the rail network, which is one of the world's largest. The AP State Road Transport Corporation arranged special buses to send the other passengers to their destinations.
The derailment is thought to have been caused by a technical fault, Mr Rao said. Train accidents are common in the country, where much of the railway equipment is obsolete. The injured have been shifted to various hospitals including Raigad (Orissa) and Parvatipuram and Visakhapatnam (both in Andhra). The driver of the Jagdalpur-Bhubaneswar train had heard "a big cracker-like sound" just before the derailment took place, sources said, adding that there was a big crack on the tracks.
Rescue workers worked through the night to locate the trapped passengers and pull them out of the wreckage.
Prime Minister Narendra Modi expressed grief over the loss of lives in the derailment of the Jagdalpur-Bhubaneswar Express.
Prabhu, who was rushing to accident site himself, has also announced ex-gratia of Rs two lakh each for the kin of those killed.
"My condolences to the families who lost their loved ones", Andhra Pradesh Chief Minister Chandrababu Naidu said on Twitter.
It ran off the track minutes after it left Odisha and entered Andhra Pradesh, from where it would have re-entered Odisha. While four coaches fell on an adjacent goods train, two sleeper coaches (S-8 and S-9) and a general coach were completely crushed.
Services were affected on Rayagada and Vijayanagaram route, with several trains diverted.