The central government has sounded a health alert in India's northeast asking authorities to take immediate precautionary measures following reports of a smallpox outbreak in Bangladesh and Myanmar, officials said Monday.

"Following the Centre's instruction, the Tripura government has made arrangements for free consultation and health checkups in all the districts and sub-divisions, especially those along the bordering areas," Tripura's Health Director Jagannath Muhuri said.

A large number of patients from Bangladesh have been taking medical treatment in various hospitals in Tripura.

"We are taking extra precautionary measures in areas where we found patients coming from Bangladesh," the health director told journalists.

The fatal smallpox has been reported in Rajshahi and Mymensingh districts of Bangladesh and Myanmar.

The World Health Organisation (WHO) has sent expert medical teams to the two countries and asked all neighbouring countries to take precautionary measures to prevent the spread of the disease.

Newspaper reports said the West Bengal government also alerted its health officials about possible outbreak of the disease, which according to WHO was eradicated in 1984.

"We have also instructed doctors and health workers to take necessary help from the Border Security Force (BSF) and Assam Rifles as and when required," Muhuri added.

He also urged the people to be careful about any person crossing over to India from neighbouring Bangladesh with symptoms of smallpox - like fever and rashes - and requested them to report to the health centre immediately.

The official said the Indian High Commission in Dhaka had informed the external affairs ministry about the spread of smallpox in Bangladesh and Myanmar last week.

India shares a 4,095 km long border with Bangladesh, of which Tripura accounts for about 856 km.