India is tightening security with extra paramilitary soldiers and police deployed across the capital after a French consulate in southern India received a letter warning against the visit of French President Francois Hollande.

Police are investigating the source of the letter, addressed to the French consulate in Bangalore and saying Hollande should not come to India.

Bangalore's additional commissioner of police, Chengal Reddy, told reporters that the letter written in poor English and mentioning al Qaeda has still not been ruled out as a hoax.

Hollande is scheduled to arrive Sunday for visit including stops in the northern city of Chandigarh and in New Delhi. He will be the guest of honor at a two-hour military parade Tuesday marking 66 years since India adopted its constitution.