LUCKNOW, India (Reuters) – Police in India said on Friday that an explosion in a train that left 13 people dead and dozens wounded was caused by a bomb planted in a toilet.

Indian railway officials had earlier suggested the blast late on Thursday near Jaunpur town in northern Uttar Pradesh state may have been caused by a cooking gas cylinder, sometimes carried by villagers on trains.

But bomb experts discounted this on Friday.

&#34There is enough evidence to confirm the use of RDX explosive,&#34 a member of a police bomb squad, who did not want to be named, told Reuters from the site.

Uttar Pradesh Home (interior) Secretary Alok Sinha said authorities did not have any specific leads on who was behind the blast which occurred in an unreserved coach.

&#34It certainly is not an accident. It is some explosive planted in the coach,&#34 Sinha told Reuters.

&#34But who could have been behind it has not been ascertained.&#34

The RDX high explosive — also known as hexogen — has been used by militants fighting Indian rule in disputed Kashmir and in the country”s restive northeast region. The rebels have frequently targetted trains in the past.

In Thursday”s explosion, witnesses said some bodies were flung from the door of the moving train after the explosion.

&#34I was waiting in my car at the railway crossing and there was suddenly a big bang,&#34 Vineet Tiwari said.

&#34I got out and went closer. It was a horrible sight. People were lying with their limbs severed. Others were crying and screaming,&#34 he said over the telephone.

Police said at least 20 of the 46 wounded were in critical condition.

In 2000, just before India”s independence day on August 15, a bomb went off in a train in Uttar Pradesh, killing 12 people and wounding 37. New Delhi blamed Muslim militants backed by Pakistan”s spy agency for the blast.