A bomb exploded on board a passenger train in central Pakistan on Monday, wounding 14 people, officials said, in what the railways minister called "an act of terrorism".
The device on the Shalimar Express from the eastern city of Lahore to Karachi went off as it passed through fields near the town of Toba Tek Singh in Punjab province.
"It was an act of terrorism. The explosive was planted in the washroom of a bogie (wagon)," railways minister Saad Rafique told reporters in Lahore.
"Fourteen people have been injured, condition of three of them is critical."
TV footage showed the explosion had damaged the roof of the carriage but not forced the train off the rails, suggesting a relatively low-intensity blast.
Farah Masood, a senior government official in Lahore, confirmed to AFP that a locally-made explosive device was used in the explosion and that 14 people had been injured.
Pakistan is battling a homegrown Islamist insurgency and faces near-daily bombings and shootings in the troubled northwest, but attacks on the railway are relatively rare.
A bomb near the waiting lounge for the luxury Lahore-Karachi Business Express train last year killed two people.