India on Thursday succesfully test fired its nuclear capable intermediate range ballistic missile Agni-III from the Interim Test Range at the Wheeler's Island in the Bay of Bengal off the Orissa coast, defence sources said.

The 16-m Agni-III weighs 48 tonnes and is capable of carrying conventional and nuclear warheads weighing up to 1.5 tonnes.

The missile has a range of over 3,000 km.

Three sophisticated radars, six electro-optical tracking systems and three telemetric data stations, located in the mainland were engaged to monitor the entire trajectory of the missile.

With an improved guidance system, this latest variant of the Agni series of missiles, Agni-III has a diameter of 1.8 m and length of 16 m.

The missile was meant to support a wide range of warhead configurations with a total payload ranging between 600 kg and 1.8 tonne and featured decoys and other anti-ballistic counter-measures, the sources said.

Agni-III missile could be deployed using rail or road mobile launch vehicles and had an inertial guidance system with improved optical or radar terminal phase correlation capability to guide it accurately to its target.

Agni's other variants are Agni-I with a range of 700 km and Agni-II with the capability to traverse 1,500 km or more.

Both the variants had been successfully test fired in the past and were in the process of being inducted into the armed forces.

While Agni-I is a part liquid and part solid fuel propelled missile, the longer range Agni-II and Agni-III have solid fuel boosters and aimers, the sources said.

With this launch, Agni-III has become the missile with the longest reach in South Asia and more powerful than any missile in Pakistan's arsenal.