"We are alarmed at the seemingly organized poaching by gangs at the Kaziranga National Park," Assam state Forest and Environment Minister Rockybul Hussain said.
The adult male rhino was killed for its horn on Tuesday, less than three weeks after a mother and its calf were brutally killed at the same park.
Rhino horns are in great demand globally, particularly in Southeast Asia, for use in traditional medicines and supposed aphrodisiacs. They are also used to make decorative dagger handles.
"We have decided to rush 100 armed guards to Kaziranga and to equip the existing forest guards with 200 better rifles to match weapons used by the poachers," Hussain said.
Last month, poachers killed a rhino calf and removed its small horn using an ax. A day later, they hacked the horn from its mother, who bled to death two days later. Another animal was killed earlier in January.
"Our veterinarians tried their best to save the bleeding female rhino, but failed. We felt miserable," said park warden S.N. Buragohain.
Kaziranga, about 135 miles east of Gauhati, the capital of Assam, has about 2,000 one-horned rhinos out of the estimated global population of 3,000, according to forest officials.
Conservation efforts have led to a rise in the rhino population and they are now found even on the periphery of the park, making them an easier target for poachers.
There was a surge in poaching last year, when 20 rhinos were killed inside the park, compared to just five in 2006.
According to government figures, 650 one-horned rhinos have been killed in Kaziranga in the past 40 years.
