Union environment minister Jairam Ramesh has asked Assam chief minister Tarun Gogoi to immediately probe into the recent death of four elephants, including two calves, in the Kaziranga National Park (KNP).

Suspecting that the jumbos had died due to poisoning, Ramesh while expressing his concern in a letter to the chief minister said, "enquiry may be immediately conducted and take the most stringent action against those found responsible for this tragedy."

The death of jumbos in the buffer areas of the world heritage site has come close on the heels of the killing of seven elephants by a speeding train at Siliguri in West Bengal.

The union minister, who had visited the park a few days back, has also offered central assistance to Assam government in investigating the death of the elephants.

In September, the government announced that the elephant would be given National Heritage Animal status, which would entitle it to the same level of protection as the tiger.