India will conduct another test launch of its intermediate-range nuclear-capable missile Agni II in September from the east coast Wheeler Island facility.

The surface-to-surface missile underwent a successful test launch in May after failed test launches last year.

The Defense Research and Development Organization, developers of the missiles, said the Agni II missile to be tested in September is an advanced version with an extended range of up to 1,800 miles over the normal 800 miles.

The short-range Agni I can hit targets up to 450 miles away.

While Agni II and Agni III are two-stage missiles, Agni I is a single-stage missile, the DRDO said.

Wheeler Island -- just over 1 mile long -- is a major test base 6 miles off the country's east coast in the Bay of Bengal and about 90 miles from Bhubaneshwar, the capital city of Orissa state.

It was from Wheeler Island that Agni III, with a range of just over 2,000 miles, was successfully test-launched from a mobile launcher in February.

The longer range of Agni III was made possible by adding a special-purpose coating of chromium metal to the blunt nose cone of the missiles to reduce drag, G. Jagadeesh, an assistant professor at the Indian Institute of Science, said in 2008.

The first test of Agni III was an unsuccessful launch in July 2006.

The solid-propellant Agni series of ballistic missiles are manufactured by Bharat Dynamics, one of India's major manufacturers of munitions and missile systems founded in 1970 in Hyderabad, Andhra Pradesh. Bharat Dynamics also manufactures India's Konkurs anti-tank missile.

India also may begin flight trials of what it calls Agni V with a range of around 3,100 miles, a military scientist said in February.

"Agni-V is out of the drawing board. We are aiming for a flight trial within a year," V.K. Saraswat, India's chief military scientist, said.

Agni missiles are claimed to be a part of India's credible deterrence against China and Pakistan. A range of more than 3,000 miles would make most of China a target.

India also has developed a supersonic cruise-type missile, the BrahMos, for closer targets.

Defense Minister A.K. Antony recently said India would export the indigenously built BrahMos, but only after all Indian military needs have been met.

Foreign sales are allowed under the 1998 agreement signed by India and Russia that set up BrahMos Aerospace to manufacture the missile, he said in a written response to a question in the country's Parliament.

The missile will be inducted in the armed forces of India and Russia.

Although some countries have shown an interest, no decisions have been made about who the customers would be or when the BrahMos will be available for export.