India's mega defence exhibition -- the DefExpo -- began here today with participation of major global and domestic military firms, which are eyeing billions of dollars of contract as part of the country's military modernisation program.

The NDA government is trying to project the 10th edition of the event as first serious attempt to transform India -- the largest importer of military platforms and weapons -- into a hub of military manufacturing.

India is expected to spend close to USD 300 billion in the next five years in procuring defence equipment and almost all major global defence firms are eyeing a slice of it.

Though the four-day-long DefExpo, on the outskirts of Chennai and close to the temple town of Mahabalipuram, began today, it will formally be inaugurated by Prime Minister Narendra Modi tomorrow.

Defence Minister Nirmala Sitharaman, in a tweet, said "For the first time, India will be showcasing its defence export potential at @DefExpoIndia."

According to the Defence Ministry, over 670 defence firms, including 154 foreign manufacturers, are participating in the exhibition of weapons and military hardware.

It is being attended by official delegations from over 47 countries, including the US, the UK, Russia, Afghanistan, Sweden, Finland, Italy, Madagascar, Myanmar, Nepal, Portugal, Seychelles and Vietnam.

The theme of the expo is "India: The Emerging Defence Manufacturing Hub."

Major international companies, which are participating at the expo include Lockheed Martin, Boeing (US), Saab (Sweden), Airbus, Rafael (France), Rosonboron Exports, United Shipbuilding (Russia), BAE Systems (UK), Sibat (Israel), Wartsila (Finland) and Rhode and Schwarz (Germany).

India's indigenously developed land, air and naval systems are also being showcased.

The weapons and platforms being displayed include the Tejas fighter jets, advanced towed artillery gun systems (ATAGS) designed by the DRDO Arjun Mark 2 tank and Dhanush artillery guns.

The DRDO's exhibits include the Nirbhay missile system with launcher, autonomous unmanned ground vehicle (AUGV), MBT Arjun Mk-I tank, Astra missile, low level transportable radar (LLTR) system, medium power radar (MPR) system and Varunastra -- heavy weight anti submarine electric torpedo.

The exhibition is spread over an area of 2.90 lakh square feet.