With just two days left for India's 69th Independence Day celebration, security has been tightened at the Red Fort where Narendra Modi will hoist the tricolour and deliver his second speech as Prime Minister.

The Ministry of Home Affairs (MHA) has issued a security alert to Delhi, Mumbai and states adjoining Indo-Pak border, particularly Jammu and Kashmir and Gujarat.

Delhi faces major terror threat this year, as at least nine suspected terrorists from Pakistan have reportedly sneaked in to the national capital.

A cache of arms and explosives, including RDX and detonators used in preparing improvised explosive devices (IEDs), purportedly for the nine terrorists, was sent to Delhi three months ago, the Mail Today has reported citing sources in the Central Industrial Security Force (CISF).

"The routine Saturday meeting at the MHA, where all the arms of Indian intelligence are present to share intelligence inputs with one another, had thrown up this input. It has since been circulated to all of us with the direction to maintain top-notch vigil and remain at the highest level of preparedness to avert any terror attack. So we have beefed up security at all the establishments that are under our watch," the Mail Today quoted a CISF source as saying.

Security forces also suspect that the terrorists have been sent to Delhi to carry out Gurdaspur-like terror attacks. Top intelligence officials have neither confirmed nor denied the latest terror threat. 

The MHA had also issued warnings of possible terror attacks on important installations in India by various terror outfits, including Indian Mujahideen (IM), Jaish-e-Mohammed (JeM), Tahrik-e-Furqan (TeF), Lashkar-e-Taiba (LeT) and Pasban-e-Ahle Hadis (PAH).

The MHA alert said that Lashkar-e-Taiba has been asked by Pakistan's Inter-Services Intelligence (ISI) to coordinate with the terror groups.

Besides, Intelligence Bureau (IB) has also warned of possible terror attack on or ahead of Independence Day, based on calls intercepted between handlers from Pakistan and the militants apparently hiding in India. The handlers have been heard asking militants to attack the Indian Army camps and convoys of other security forces.

Heavy security for PM

The 2015 Independence Day speech, which will be Modi's second as Prime Minister, will see heigtened security arrangements in view of the increased threat perception.

At least 200 specially trained commandos of National Security Guard (NSG), Special Weapons and Tactics (SWAT) and Border Security Force (BSF) will be deployed within 500 metres of the fort as part of the five-tier security cover for the prime minister.

The commandos will be armed with Beretta assault rifles and high-tech communication gadgets. They will be in body armour, protective helmets, knee pads and gloves.

In addition, Modi will be provided with bullet-resistant glass shield on the stage, unlike last year when he addressed the gathering without one.

"This time, we want the bullet-resistant glass enclosure back in its place to ensure better security for the PM, who continues to face threats from terrorists and extremists. As of now, no final decision has been taken on its insertion but we continue to insist," a home ministry official told HT.

Intelligence agencies' special commandos

The intelligence agencies are also deploying special commandos on Independence Day for the first time in the history of independent India.

"The special commandos have expertise in neutralising suspects by firing from multi-body positions," the Hindustan Times quoted a senior police officer as saying.

Security agencies have established a no-fly zone over Delhi for the Independence Day celebration. Two ultra high-resolution cameras will be placed at the two towers of the Red Fort to keep a vigil.

Over 100 specially designed metal detectors will be installed in and around the Red Fort. At least 6,000 security personnel from Delhi Police and paramilitary forces will be deployed in and around the fort and the routes that will be taken by Modi's cavalcade and other VVIPs.

Over 1,000 CCTV cameras for surveillance

The route will also be equipped with CCTV cameras. More than 300 CCTV cameras have already been installed and installation of nearly 700 is in progress.

The inputs from all these CCTV cameras will be monitored by senior officials at a control room that has been set up at the Red Fort.

India recently witnessed a spate of terror attacks, including one at Gurdaspur in Punjab and the other at Udhampur in Jammu and Kashmir.