Nine people have been killed and 38 others injured in an explosion on a moving passenger train in India, a senior police official has said.
The blast occurred when the train was near Jaunpur, in northern Uttar Pradesh state, about 640km (400 miles) east of the capital Delhi.
The cause of the blast, which occurred in an unreserved compartment of the train, is unclear.
Relief and rescue teams have been sent to the scene.
The train was travelling from Patna in eastern Bihar state to Delhi.
Uttar Pradesh police chief Yashpal Singh said nearly 40 people had been injured, some of them seriously.
"We still can't say if it was a bomb that exploded in the toilet of an unreserved coach," he told Reuters news agency.
"It could be that somebody was carrying an explosive."
Railways Minister Lalu Prasad Yadav had earlier told reporters in the eastern city of Patna that it was unclear whether the explosion was caused by a bomb or by the gas cylinder of a cooking stove, sometimes carried by villagers on trains in India.
Rajendra Singh, a senior railways official, told Reuters news agency: "There was a blast on an unreserved coach, but it wasn't a very big explosion.
"Luckily it was not very crowded. The coach didn't jump off the rail."
Another railways spokesman, Geetanjali Kame, said the train had been able to continue to the nearest station.