Clinton has visited India twice before

One of Mr Clinton's aides, David Slade, has written to officials in India saying that the decision had been made at the request of the United States Secret Service, according to the AFP news agency.

Mr Clinton was due to attend the "India Today Conclave", a three-day event organised by the India Today weekly magazine later this month.

As president, Mr Clinton visited India twice. Firstly on an official visit in 2000 and on an unofficial trip the following year.

It is reported that Mr Slade wrote to officials in India saying: "At the request of the United States Secret Service, a visit to India by former President Bill Clinton has been cancelled due to serious security concerns."

The US embassy in Delhi said it had heard the reports, but told the BBC it could not confirm the news. Discussion forum

The India Today Conclave event is due to run from 28 February to 1 March.

The annual occasion brings together figures from the worlds of politics, business and entertainment and provides a forum for discussions on international affairs.

Mr Clinton was due to address the conference on 1 March.

In April 2001 Mr Clinton held talks with Prime Minister Atal Behari Vajpayee.

But the main focus of the week-long trip was to raise money for the victims of the earthquake earlier the same year in Gujarat state.

Mr Clinton also visited an orphanage set up by the late Mother Theresa of Calcutta.