NEW DELHI (AP) — 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 were investigating the source of the letter, addressed to the French Consulate in Bangalore and saying that Hollande should not come to India.

The letter was written in poor English and mentioned al-Qaida, according to Bangalore's additional commissioner of police, Charan Reddy.

"We haven't ruled out that it's a hoax letter," Reddy said.

Security has been stepped up at the Bangalore consulate with paramilitary police posted on guard duty, he said.

Hollande is scheduled to arrive Sunday for a three-day visit, including stops in the northern city of Chandigarh and New Delhi. On Tuesday, Hollande is expected to be the guest of honor at a two-hour military parade for India's Republic Day, marking 66 years since the South Asian country adopted its constitution.

Home Minister Rajnath Singh and Delhi police officials said they have reviewed security arrangements for the parade, including positioning army sharpshooters on rooftops near the parade route and clearing buildings and roads. During the parade, authorities also plan to put the city under a complete lockdown, a police official said on condition of anonymity as he was not authorized to speak to the media.

Separately, police arrested four men in the northern state of Uttarakhand on Wednesday on suspicion of planning an attack in New Delhi. Security officials said the four had been under surveillance for several months after their online activities drew suspicion, including contacts with people in territory in Iraq and Syria controlled by the Islamic State group, the Press Trust of India news agency quoted police as saying.

Police said the men had also been planning strikes in the Hindu holy city of Haridwar in northern India, where thousands of devotees are now gathered for a religious festival.