The Agni-III, which has a range of 3,500 km (over 2,200 miles) and can carry a 1,000 kg payload, is the most powerful missile developed by India's Defense Research and Development Organization (DRDO).
"The missile meets our regional tasks and satisfies the demands of our national defense," K. Santhanam, former chief advisor at DRDO, said in a television broadcast.
With a range of over 2,000 miles, the Agni III is capable of carrying nuclear warheads across much of Asia and the Middle East.
The first test of the missile, which is equipped with solid boosters, in July 2006 was unsuccessful. The second stage failed to separate from the missile in time and fell short of its target.
However, the second test in April 2007 was described as successful.
Earlier versions of the Agni series, Agni I and Agni II, with a range of 700 km (430 miles) and 2,500 km (over 1,500 miles) respectively, have already been put in service with the Indian Army.
According to Indian media reports, the Agni III can be mounted on railroad platforms and its modified version can be placed on board a nuclear submarine, codenamed the Advanced Technology Vehicle (ATV), expected to undergo sea trials this year before its induction into the Indian Navy in 2009.