The Thar desert boomed with artillery guns as tanks kicked up dust and fighter aircraft flew on bombing runs.
It may have looked like war, but it was actually an elaborate simulation to demonstrate to international observers that India has become a major military power.
Observers from 60 countries watched Wednesday's war games, code-named "Brazen Chariots," in Pokharan, the site in the western desert of Rajasthan where India conducted a series of underground nuclear tests in 1998.
The area is 60 miles from Pakistan, but officials said the war games were not directed at their neighbor. The nuclear-armed rivals have fought three wars since independence in 1947.
"We are not sending out any message," said Indian army chief Deepak Kapoor. "It is purely to see what kind of synergy the Indian air force and the army are able to achieve when put together."
An accident marred the exercise, however.
Three soldiers were killed and two others injured when a 5-inch mortar gun exploded, army spokesman Virender Singh said, adding the army ordered an inquiry into the accident.
With India emerging as one of the world's biggest buyers of military hardware, international aviation and military equipment manufacturers are seeking a share of billions of dollars in potential defense contracts.
One of world's largest armies
India has been holding joint war games with several countries whose representatives were invited for the exercise, including the United States and China, which India fought in a brief but bloody border war in 1962.
Military observers from South Africa, Italy, Germany, Myanmar, Malaysia, Thailand, Kenya and Kuwait and a number of other countries also watched Wednesday's exercise.
India's 1.3 million-member army is one of the world's largest but is hampered by outdated equipment, much of it Soviet-era relics. In recent years, India has gone on a major arms buying spree to update its weaponry.
It plans to spend $26 billion on defense in the next fiscal year, up 10 percent from the current budget.
"I think India is displaying the professionalism of its armed forces. It is pushing forward its forging relations with lots of foreign countries," said Brigadier Richard Nugee of the British army. "That's a very good thing."