New Delhi, (PTI) : The Defence Research and Development Organisation (DRDO) has yet again put off fresh trials of the country's most potent missile -- the nuclear-capable Agni-III with a range of over 3,000 km.

Highly placed sources said the missile's second trial had tentatively been scheduled for the year-end or early next year but this has been delayed as scientists are yet to fully analyse the causes of the failure of its maiden test in July.

The Agni-III had crashed into the sea during its first teat when its second stage failed to separate.

Though the government has announced another year-long extension for DRDO's prestigious Integrated Guided Missile Development Programme (IGMDP), some key components for the Akash surface-to-air missile and Nag anti-tank missile are reportedly running behind schedule along with heavy cost overruns.

The short-range Prithvi I and II surface-to-surface missiles and the medium-range version of Agni-I (with a reach of 700 km) and Agni-II (1,500 km) are now being inducted into the armed forces, but clouds still loom over the induction of the Akash and Nag missiles.

The long delays in the missile programme have begun to have telling effects on the modernisation drive of the armed forces and this has been expressed by IAF chief, Air Chief Marshal S P Tyagi.

Tyagi said the country's preparedness to counter low- level air attacks had received a setback as the Akash missile's induction had again been delayed.

The Akash programme was launched in the early 1980s and the missile was expected to enter service in the early 1990s. But the missile did not pass acceptance trials by the armed forces in 2004 and 2005.