Five persons, including four tourists from Gujarat, were killed and 21 others injured in a powerful explosion inside a tourist bus outside the famous Shalimar garden in summer capital Srinagar [Images] on Sunday afternoon.

Inspector General of Police (Kashmir zone) told rediff.com, "The cause of the explosion is still being ascertained. Two female tourists from Gujarat and a local woman were among the five killed in the explosion. 21 others are wounded."

The injured tourists were immediately taken to Soura Medical Institute and the SMHS hospital in Srinagar.

While four tourists died in the SMHS hospital, another critically injured local woman succumbed to her injuries at the Soura Medical Institute.

"We were sitting inside the bus when we heard a massive bang and then hell broke loose inside as everyone tried to jump out. I saw bleeding fellow tourists crying for help. There was absolute confusion inside," said Noor-ud-Din, a tourist from Gujarat.

The explosion outside the famous Shalimar garden led to heavy panic in the entire area. Thousands of locals and tourists, both domestic and foreign, throng the garden during the weekend.

Security forces carried out massive searches in and around the Shalimar garden even as forensic teams examined the ill-fated bus to ascertain the cause of the explosion.