Veterinarians struggled Wednesday to save the life of a rare rhinoceros that was shot and had its horn cut off by poachers after it wandered out of a flooded national park in northeastern India.

The attack on the one-horned rhino sparked outrage in the state of Assam, home to the world's largest concentration of the rare rhino. Footage of the bleeding rhino with its horn removed and a cut to its ear were broadcast on local television.

"It is a sad day for Assam. I am appalled at the fact that poachers could get away with the horn of a live rhino," said Somyadeep Dutta, an environmentalist.

Heavy rains across Assam have caused flooding in recent days that killed 18 people and forced 1.4 million to flee their homes.

Much of the 480 square kilometer (185 square mile) Kaziranga National Park was also flooded, drowning two rhinos and at least a dozen other animals, mostly deer, said Suresh Chand, Assam's chief wildlife warden.

Many other animals migrated to higher ground. The rhino was one of them, leaving the park for a highland across a busy highway, where trailing guards lost track of it, Chand said.

The rhino was then shot by poachers, who extracted its horn while it was still alive. Rhino horn powder is coveted in some Asian countries as a medicine or an aphrodisiac and its popularity has led to a rise in rhino poaching.

Veterinarians were rushed to the rhino's side to try to save its live, Chand said.

An estimated 2,500 out of the world's 3,000 one-horned rhinos live in Kaziranga.

A total of 13 have been killed by poachers around the park in the past nine months, a trend that has caused worry among environmental groups.

Dutta, the environmentalist, demanded a probe into the incident by India's Central Bureau of Investigation.

"The existence of organized poaching syndicates has only been proved by Wednesday's gruesome incident," Dutta said.