Two rare rhinos brutally attacked by poachers this week in northeast India have died, veterinarians said Saturday, triggering protests at local authorities' failure to protect the animals.

The one-horned rhinos were found bleeding from gunshot injuries and huge wounds on their snouts after poachers cut off their horns, nose and ears in the flooded Kaziranga national park in Assam state.

"Both the rhinos died late Friday," Bhaskar Dutta, one of the veterinarians involved in the effort to help the animals, told AFP from Assam's largest city Guwahati.

The two rhinos, listed as a "vulnerable" species, had been mutilated as they fled rising floodwaters in the park.

Animal rights groups and residents near the state-protected park staged protests denouncing the government for failing to combat poaching. They blocked highways and burnt effigies of the state forest minister.

"It's a tragedy that even after 72 hours, vets failed to reach the injured rhino while local TV channels were beaming live images of the helpless animals," said Sanjiv Das, a community leader in Kaziranga.

"We want an explanation from the state government about why they could not treat the two rhinos and save them."

There were conflicting reports about whether the rhinos, aged between 20-25, had received treatment.

While veterinarian Dutta said the rhinos had not been treated, the state conservator of forests Ramen Das said on Friday that vets operated on the animals to remove bullets from their abdomen and were treating other wounds.

Das was not available to comment on Saturday.

The 430-square-kilometre (166 square-mile) park in eastern Assam is home to the largest concentration of the world's remaining one-horned rhinos.

Around 600 animals in Kaziranga, including 14 one-horned rhinos, were killed in the wake of floods in July this year. A majority were mowed down on a nearby highway by speeding vehicles as they left the park for higher grounds.

A 2012 census in the park put the number of the rhinos at 2,290 out of a global one-horned rhinocerous population of 3,300.

The species fell to near extinction in the early 1990s and is currently listed as "vulnerable" by the International Union for Conservation of Nature.

Kaziranga has fought a sustained battle against rhino poachers who kill the animals for their horns, which fetch huge prices in some Asian countries where they are prized for their supposed aphrodisiac and medicinal qualities.

The rhino deaths come as Assam battles severe monsoon flooding, which has swamped 19 of the state's 27 districts and displaced two million people over the last two weeks, according to official figures.