Mar 29, Sigiriya: Tourists to the world famous Sigiriya rock fortress came under another wasp attack this morning at the top of the rock, the police said.

This time three visitors, all foreigners, were injured and have been admitted to the Sigiriya Hospital, police confirmed. Several others who were trapped on the top have been evacuated by police and Air Force personnel, soon after the incident.

This is the third time the wasps attacked in five days at the top of the Sigiriya rock. At least 50 people including school children have been admitted to the hospital last week when wasps attacked them near the Lion's Paw.

The rock and the surrounding areas are home to wasp colonies and the visitors to the rock are instructed not to be noisy to keep the wasps undisturbed.

Authorities however prevent from using chemical means to exterminate the wasps for the fear of damaging the world famous 5th century paintings on the rock walls.