The guards of the park spotted the carcass during a routine patrolling on Friday.

Preliminary investigation suggested that the animal was killed in the last 48 hours and the poachers had managed to take away its horn, the park officials said.

"The carcass was recovered from an area in park's Agaratoli forest range. There were bullet marks on the carcass and the horn was missing. This indicates it is a case of poaching," said an official.

He said that the forest guards had heard gunshots on Wednesday night, and subsequently carried out a search operation but found nothing.

This is the 15th one-horned rhino to have fallen prey to the bullets of poachers in Kaziranga so far this year.

Assam Forest Minister Pramila Rani Brahma rushed to the park on being told about the incident. "It is very unfortunate that we are losing our rhinos. We have been taking steps to check poaching, but the poachers still killed the rhino," she said.

Assam Chief Minister SarbanandaSonowal asked the state police as well as the state Forest Department officials to take urgent steps and stop the menace of poaching of one-horned rhinos.

He recently took up the matter of poaching with Nagaland Chief Minister T.R. Zeliang, as most of the rhino horns are smuggled out of the state through Nagaland.

The Kaziranga National Park in Assam has the highest number of single-horn rhinos in the world. The horns of these rhinos are in great demand in Southeast Asian countries for use in traditional medicines.

According to Forest Department officials, a rhino horn is sold for as much as Rs 1 crore or more in the international market.