India on Sunday test-fired an upgraded version (with better re-entry technology and manoeuvrability) of the nuclear capable surface-to-surface short range Agni-I missile.

Agni-I is a short-range variant of the intermediate-range missile (Agni). Compared it its longer-range cousins, its height is just 12metres. Secondly, it is powered by a single stage solid fuel rocket, which imparts it a speed of 2.5km per second. It has a range of 700-900km.

It was first test-fired on January 25, 2002 and then on January 9, 2003.

On Sunday, it was fired at 1010 IST from a mobile launcher at the Integrated Test Range located at Wheeler's Island in the Bay of Bengal off the Orissa coast.

"Today's flight was a text book launch," Mission Director R N Agarwal told PTI.

DRDO officials said ground radars, telemetry stations and naval ships positioned close to the intended impact point monitored the course of the missile.

Scientific advisor to the defence ministry A V Atre said the missile was tested in a user mode, specifically for the army and hence the use of mobile launchers.

A Pune-based DRDO establishment has recently developed specialised launchers for the Agni-I and Indo-Russian supersonic cruise missile BrahMos.

"The prime mission objective for the 3rd serial flight of Agni-I was to reconfirm the technical parameters set for this user (Army) associated launch," the DRDO official said.

Agni-I is expected to bridge the gap between indigenously built short-range Prithvi, already deployed in the army, and the intermediate range Agni-II which has a range of more than 2,000km, sources said.

It can blast off from both road and rail mobile launchers. Weighing less but having the same thrust, the missile has added acceleration.

The Defence Research and Development Organisation had launched the Agni project in 1983 as part of the country's Integrated Guided Missile Development Programme and the first test flight of the missile was conducted on May 22, 1989.

After two more trials on May 22, 1992 and February 19, 1994, an extended version of the missile named Agni-II was successfully test-fired with a re-entry launch vehicle in April 1999. A second test of this extended range Agni-II was conducted on January 17, 2001, the sources said.

Prime Minister Manmohan Singh and Defence Minister Pranab Mukherjee have congratulated defence scientists for the successful test-firing of the missile.