Italian killed by Isis
Italian national Tevella Cesare who was shot dead by Isis militants in Bangladesh.Twitter/Rita Katz SITE

Ever since the Islamic State took responsibility for killing an Italian aid worker in Bangladesh's capital city of Dhaka, Indian intelligence agencies fear the possibility of lone-wolf attack in India by Isis sympathisers.

Their fear seems to have originated from the rising number of Indian youths allegedly being radicalised by the Isis through social media.

"There is a clear and present danger of a radicalised individual or group, swayed by IS' ideology of violent extremism, attempting a lone-wolf attack in India. The agencies are alert and are pro-actively tracking such suspect elements, especially their online exchanges, and intervening the moment they betray signs of joining the IS or travelling to Iraq/Syria," The Times of India quoted a senior officer as saying.

Three unidentified men, riding on a motorbike, shot dead Cesare Tavella, the Italian aid worker, in Dhaka on Monday. The Islamic State took the responsibility of the killing. However, Bangladeshi government said they have no evidence to confirm Isis' claims.

"The claim has not been confirmed, there is no such evidence," Home Minister Asaduzzamn Khan had told reporters on Tuesday, according to AP report.

On Monday, Isis said in a statement that a "security detachment" had tracked and killed Cesare Tavella with "silenced weapons," according to the SITE Intelligence Group's website, AP reported.

Indian intelligence agencies believe that Tavella's killers were Isis sympathisers, not active members of the outfit, as Tavella was not beheaded -- Isis' infamous style of execution. This has got them worried as several cases of Indian youths being radicalised by Isis through social media have come up in recent days.

While at least 10 Indians are believed to be within the Islamic State territory in Syria or Iraq, as many as 30 youths were found to be sympathisers of the Islamic outfit, but their attempts to join it were foiled. Recently, United Arab Emirates deported at least 10 Indian youths on the suspiscion that they were in contact with the Isis radicals.

"There has been no concrete evidence of IS' direct presence in Bangladesh. But the country does have a worrying proliferation of radical Islamic groups who pose a clear terror threat. The killing of the Italian may have been a lone-wolf attack by an IS sympathizer," a senior intelligence officer told.

Deceased Italian aid worker Tavella was in Bangladesh since August and was working with Netherlands-based church cooperative - Interchurch Organisation for Development Cooperation, or ICCO -- in Dhaka.