The incident took place near Borgho forest camp under Burapahar range of the park around 1.15am.

Of the five rhinos killed in the park this year, three were attacked in this range.

"People involved in the killing of the rhino were not poachers but militants armed with AK-47 rifles. Our men engaged in a gun-battle with the group but they were firing from AK-47 rifles and our men had to give up the chase," Burapahar range officer Jinaram Bordoloi told The Telegraph.

In the last rhino killing in the range on January 11, militants had fired from light machine guns and AK-47 rifles during a confrontation with forest guards.

The incident had prompted the forest department to take the help of the army.

Today, Bordoloi said gunshots were heard in the dead of the night following which forest guards rushed towards the spot from where the sound had came.

They were greeted by a hail of bullets from AK-47 rifles.

"The poachers were fleeing towards Karbi Anglong hills and firing at random at our men. Our men continued the chase but had to give up as the militants resorted to heavy firing from AK-47 rifles," the forest official said.

A search party later found the carcass of a male rhino with its horn missing.

Senior forest officials today held a closed door meeting with forest minister Atuwa Munda to discuss ways to check rampant killing of rhinos.

Munda said he has convened a meeting at Dispur tomorrow where the head of the Rhino Task Force and additional director-general of police (special task force), A.P. Rawat, and his predecessor and ADG (law and order), R.M. Singh, will be present, apart from principal chief conservator of forest and director, Kaziranga National Park.

"Rawat told me he has just taken over and so it would be better if Singh also attends the meeting as he had headed the task force for some time," Munda said.

"We will discuss threadbare about poaching and what could be done to stop it," the minister said.

He said how to go about taking the army's help would also be discussed.

"There is a certain protocol involved in deploying the army and we will see how we can do it," he said.

Altogether 32 rhinos were killed last year and 41 in the previous year in Assam and most of these killings took place at Kaziranga.

The spate of rhino killings has triggered protests in the state.

Assam governor Padmanabha Balakrishna Acharya, expressing deep concern, hurt and anger, had instructed the authorities to identify the persons accountable for such heinous crimes and punish them severely.

Chief minister Tarun Gogoi has also asked the Kaziranga authorities to take the help of National Investigation Agency (NIA) to deal with rhino poachers and bust their trade routes across inter-state and international borders.

He had recently said that his government had sent a proposal to the Union ministry of environment, forests and climate change to set up a special rhino protection force with 1,200 personnel.

Last week, Gogoi had held a review meeting at Kohora range of the park on anti-poaching measures.

He directed the district administrations concerned to sanitise the areas adjoining the park by deploying a young and energetic commando force.