"We advise you to exercise a high degree of caution in India at this time because of the high risk of terrorist activity by militant groups," the advisory by US government said.
Similarly, Canada and Australia have advised its citizen to be alert while visiting India.
"We continue to receive reporting of possible threats against prominent business and tourist locations, including in Mumbai and New Delhi," the Australian advisory said.
Foreign and Commonwealth Office of the UK government had also issued a warning in its website warning of tourist of suspected future terror attacks in most frequented places by foreigners.
Refuting such alerts, External Affair SM Krishna said on Wednesday that foreigners should come and visit the country without fear.
"Let me scotch all speculative reports that India is a country infested by terrorists. I would like to reject this totally. You find thousands of foreigners who have been freely going about wherever they feel like. I would like to assure the foreign tourists, visitors and others that they don't have to worry about it," Krishna said in New Delhi on Wednesday, Dec 30.